Unconditionally call setException for RejectedExecutionException.

Under JDK11, the write to thrownByExecute / thrownFromDelegate is upsetting TSAN. I *suspect* that TSAN is incorrect (and that it is likely to identify the same "problem" in other code).

However, we years ago questioned whether the code I'm removing served any real purpose...
(fixes #2877)
...so now seems like a good time to get rid of it and, at minimum, hopefully eliminate the current TSAN failure.

The code that we're running in the executor is under our control. (That is, we're the ones who implement Runnable.run().) We're catching exceptions (and thus any RejectedExecutionException) in the obvious places. Occasionally we do call listeners, but naturally we do that only after completing the future or at least calling setFuture (after which a stray setException(rejectedExecutionException) would be a no-op).

The one(?) exception to that is that InterruptibleTask.run() can call currentThread.interrupt(), which we learned a few years ago can call arbitrary code through nio callbacks. At some point, though, I throw my hands up and say "whatever."

(If the interrupt were to be a problem, it would have to be with an executor that executes tasks inline, like directExecutor. But I note that rejectionPropagatingExecutor, at least, already defends against this for directExecutor itself (by skipping the RejectedExecutionException logic entirely). So the danger exists only with CombinedFutureInterruptibleTask or with a non-directExecutor that can execute tasks inline without catching exceptions -- and again, only in concert with nio interrupt callbacks. I think.)

RELNOTES=n/a

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=321374425

android/guava/src/com/google/common/util/concurrent/CombinedFuture.java

@@ -89,7 +89,6 @@ protected void interruptTask() {
   @WeakOuter
   private abstract class CombinedFutureInterruptibleTask<T> extends InterruptibleTask<T> {
     private final Executor listenerExecutor;
-    boolean thrownByExecute = true;
 
     CombinedFutureInterruptibleTask(Executor listenerExecutor) {
       this.listenerExecutor = checkNotNull(listenerExecutor);
@@ -104,9 +103,7 @@ final void execute() {
       try {
         listenerExecutor.execute(this);
       } catch (RejectedExecutionException e) {
-        if (thrownByExecute) {
-          CombinedFuture.this.setException(e);
-        }
+        CombinedFuture.this.setException(e);
       }
     }
 
@@ -153,7 +150,6 @@ private final class AsyncCallableInterruptibleTask
 
     @Override
     ListenableFuture<V> runInterruptibly() throws Exception {
-      thrownByExecute = false;
       ListenableFuture<V> result = callable.call();
       return checkNotNull(
           result,
@@ -184,7 +180,6 @@ private final class CallableInterruptibleTask extends CombinedFutureInterruptibl
 
     @Override
     V runInterruptibly() throws Exception {
-      thrownByExecute = false;
       return callable.call();
     }
 

android/guava/src/com/google/common/util/concurrent/MoreExecutors.java

@@ -973,31 +973,12 @@ static Executor rejectionPropagatingExecutor(
       return delegate;
     }
     return new Executor() {
-      boolean thrownFromDelegate = true;
-
       @Override
-      public void execute(final Runnable command) {
+      public void execute(Runnable command) {
         try {
-          delegate.execute(
-              new Runnable() {
-                @Override
-                public void run() {
-                  thrownFromDelegate = false;
-                  command.run();
-                }
-
-                @Override
-                public String toString() {
-                  return command.toString();
-                }
-              });
+          delegate.execute(command);
         } catch (RejectedExecutionException e) {
-          if (thrownFromDelegate) {
-            // wrap exception?
-            future.setException(e);
-          }
-          // otherwise it must have been thrown from a transitive call and the delegate runnable
-          // should have handled it.
+          future.setException(e);
         }
       }
     };

guava/src/com/google/common/util/concurrent/CombinedFuture.java

@@ -89,7 +89,6 @@ protected void interruptTask() {
   @WeakOuter
   private abstract class CombinedFutureInterruptibleTask<T> extends InterruptibleTask<T> {
     private final Executor listenerExecutor;
-    boolean thrownByExecute = true;
 
     CombinedFutureInterruptibleTask(Executor listenerExecutor) {
       this.listenerExecutor = checkNotNull(listenerExecutor);
@@ -104,9 +103,7 @@ final void execute() {
       try {
         listenerExecutor.execute(this);
       } catch (RejectedExecutionException e) {
-        if (thrownByExecute) {
-          CombinedFuture.this.setException(e);
-        }
+        CombinedFuture.this.setException(e);
       }
     }
 
@@ -153,7 +150,6 @@ private final class AsyncCallableInterruptibleTask
 
     @Override
     ListenableFuture<V> runInterruptibly() throws Exception {
-      thrownByExecute = false;
       ListenableFuture<V> result = callable.call();
       return checkNotNull(
           result,
@@ -184,7 +180,6 @@ private final class CallableInterruptibleTask extends CombinedFutureInterruptibl
 
     @Override
     V runInterruptibly() throws Exception {
-      thrownByExecute = false;
       return callable.call();
     }
 

guava/src/com/google/common/util/concurrent/MoreExecutors.java

@@ -1078,31 +1078,12 @@ static Executor rejectionPropagatingExecutor(
       return delegate;
     }
     return new Executor() {
-      boolean thrownFromDelegate = true;
-
       @Override
-      public void execute(final Runnable command) {
+      public void execute(Runnable command) {
         try {
-          delegate.execute(
-              new Runnable() {
-                @Override
-                public void run() {
-                  thrownFromDelegate = false;
-                  command.run();
-                }
-
-                @Override
-                public String toString() {
-                  return command.toString();
-                }
-              });
+          delegate.execute(command);
         } catch (RejectedExecutionException e) {
-          if (thrownFromDelegate) {
-            // wrap exception?
-            future.setException(e);
-          }
-          // otherwise it must have been thrown from a transitive call and the delegate runnable
-          // should have handled it.
+          future.setException(e);
         }
       }
     };