[ VM ] Fix issue where ExitCodeHandlerEntry could get stuck in an

infinite loop if wait(...) returned an error

Fixes #41978

Change-Id: Ied4cc53dcfbbb6e04179721a00f04a8cd0ef9f29
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/155282
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Ben Konyi <bkonyi@google.com>

Author: bkonyi

runtime/bin/process_android.cc

@@ -231,6 +231,8 @@ class ExitCodeHandler {
             process_count_--;
           }
         }
+      } else if (pid < 0) {
+        FATAL1("Wait for process exit failed: %d", errno);
       }
     }
   }

runtime/bin/process_linux.cc

@@ -231,6 +231,8 @@ class ExitCodeHandler {
             process_count_--;
           }
         }
+      } else if (pid < 0) {
+        FATAL1("Wait for process exit failed: %d", errno);
       }
     }
   }

runtime/bin/process_macos.cc

@@ -227,6 +227,8 @@ class ExitCodeHandler {
             process_count_--;
           }
         }
+      } else if (pid < 0) {
+        FATAL1("Wait for process exit failed: %d", errno);
       }
     }
   }