Recognize Task<->ValueTask adaptions in async versions

src/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.cs

@@ -23,6 +23,11 @@ internal enum ContinuationFlags
         ContinueOnThreadPool = 1 << 0,
         ContinueOnCapturedSynchronizationContext = 1 << 1,
         ContinueOnCapturedTaskScheduler = 1 << 2,
+        // This is an await of valueTask.AsTask() (e.g. valueTask.AsTask()
+        // returned from an async version). This flag affects how
+        // ValueTaskSourceContinuation handling computes the flags to pass to
+        // IValueTaskSource.OnCompleted.
+        ValueTaskAdaptedToTask = 1 << 3,
 
         AllContinuationFlags = ContinueOnThreadPool | ContinueOnCapturedSynchronizationContext | ContinueOnCapturedTaskScheduler,
 
@@ -832,7 +837,8 @@ internal unsafe bool HandleSuspended(ref RuntimeAsyncAwaitState state)
                         // the direct AsyncHelpers.Await(ValueTask/ValueTask<T>) path.
                         // In either case, that can only happen in nontransparent/user code.
                         Continuation contWithContinueFlags = valueTaskSourceCont;
-                        while ((contWithContinueFlags.Flags & ContinuationFlags.AllContinuationFlags) == 0 && contWithContinueFlags.Next != null)
+                        while ((contWithContinueFlags.Flags & (ContinuationFlags.AllContinuationFlags | ContinuationFlags.ValueTaskAdaptedToTask)) == 0 &&
+                               contWithContinueFlags.Next != null)
                         {
                             contWithContinueFlags = contWithContinueFlags.Next;
                         }

src/coreclr/inc/corinfo.h

@@ -1786,6 +1786,9 @@ enum CorInfoContinuationFlags
     // If this bit is set the continuation context is a TaskScheduler that
     // we should continue on.
     CORINFO_CONTINUATION_CONTINUE_ON_CAPTURED_TASK_SCHEDULER = 1 << 2,
+    // If this bit is set this is an await of valueTask.AsTask()
+    // (common pattern when returning a value-task in an async version)
+    CORINFO_CONTINUATION_VALUETASK_ADAPTED_TO_TASK = 1 << 3,
 
     // The flags encode where in the continuation various members are stored.
     // If the encoded index is 0, it means no such member is present.