Report CORINFO_ASYNC_SAVE_CONTEXTS when needed (#121613)

This was added in #121448 on the VM side, managed side needs a matching
change (I actually found this because we had a newly failing test, yay).

Cc @dotnet/ilc-contrib @jakobbotsch

Author: MichalStrehovsky

src/coreclr/tools/Common/JitInterface/CorInfoImpl.cs

@@ -807,6 +807,16 @@ private bool Get_CORINFO_METHOD_INFO(MethodDesc method, MethodIL methodIL, CORIN
             {
                 methodInfo->options |= CorInfoOptions.CORINFO_GENERICS_CTXT_FROM_METHODTABLE;
             }
+
+            // Indicate this is an async method that requires save and restore
+            // of async contexts. Regular user implemented runtime async methods
+            // require this behavior, but thunks should be transparent and should not
+            // come with this behavior.
+            if (method.IsAsyncVariant() && method.IsAsync)
+            {
+                methodInfo->options |= CorInfoOptions.CORINFO_ASYNC_SAVE_CONTEXTS;
+            }
+
             methodInfo->regionKind = CorInfoRegionKind.CORINFO_REGION_NONE;
             Get_CORINFO_SIG_INFO(method, sig: &methodInfo->args, methodIL);
             Get_CORINFO_SIG_INFO(methodIL.GetLocals(), &methodInfo->locals);

src/coreclr/tools/Common/JitInterface/CorInfoTypes.cs

@@ -438,6 +438,7 @@ public enum CorInfoOptions
                                                    CORINFO_GENERICS_CTXT_FROM_METHODDESC |
                                                    CORINFO_GENERICS_CTXT_FROM_METHODTABLE),
         CORINFO_GENERICS_CTXT_KEEP_ALIVE = 0x00000100, // Keep the generics context alive throughout the method even if there is no explicit use, and report its location to the CLR
+        CORINFO_ASYNC_SAVE_CONTEXTS = 0x00000200, // Runtime async method must save and restore contexts
     }
 
     // These are used to detect array methods as NamedIntrinsic in JIT importer,