[DO NOT LAND] Set @@toStringTag for DOM object prototypes

LayoutTests/webaudio/audiocontext-suspend-resume-expected.txt

Index: LayoutTests/webaudio/audiocontext-suspend-resume-expected.txt
diff --git a/LayoutTests/webaudio/audiocontext-suspend-resume-expected.txt b/LayoutTests/webaudio/audiocontext-suspend-resume-expected.txt
index 29a78bd90403d980bfffe7ae3af7ad3944f7a491..2b3c3cbe5620a6a7529c5c787ee0580911604423 100644
--- a/LayoutTests/webaudio/audiocontext-suspend-resume-expected.txt
+++ b/LayoutTests/webaudio/audiocontext-suspend-resume-expected.txt
@@ -5,10 +5,10 @@ On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE
 
 PASS context.state is "suspended"
 PASS p1 = context.suspend() did not throw exception.
-PASS [object Object] is an instance of function Promise() { [native code] }
+PASS [object Promise] is an instance of function Promise() { [native code] }
 PASS context.suspend() was correctly rejected for an offline context
 PASS p2 = context.resume() did not throw exception.
-PASS [object Object] is an instance of function Promise() { [native code] }
+PASS [object Promise] is an instance of function Promise() { [native code] }
 PASS context.state is "suspended"
 PASS context.resume() was correctly rejected for an offline context
 PASS context.state is "closed"