Load the global proxy from the context of the target function.

src/v8globals.h

Index: src/v8globals.h
diff --git a/src/v8globals.h b/src/v8globals.h
index 4910cb7358de7e019a41010126fceb651b75a5f1..1896c1f1e515b76e0448b4b40c8950765aafb2f3 100644
--- a/src/v8globals.h
+++ b/src/v8globals.h
@@ -293,8 +293,10 @@ enum CallFunctionFlags {
   // Receiver might implicitly be the global objects. If it is, the
   // hole is passed to the call function stub.
   RECEIVER_MIGHT_BE_IMPLICIT = 1 << 0,
+  // Receiver is implicit and the hole has been passed to the stub.
+  RECEIVER_IS_IMPLICIT = 1 << 1,
   // The call target is cached in the instruction stream.
-  RECORD_CALL_TARGET = 1 << 1
+  RECORD_CALL_TARGET = 1 << 2
 };