[proxies] fix access issue when having proxies on the prototype-chain of global objects.

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index 927989f367f053979a87e6c357433581e1074a0d..3fa26d977f1b8d59932095c1735137adf236878d 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -779,10 +779,10 @@ bool Isolate::MayAccess(Handle<Context> accessing_context,
   // Check for compatibility between the security tokens in the
   // current lexical context and the accessed object.
 
+  // During bootstrapping, callback functions are not enabled yet.
+  if (bootstrapper()->IsActive()) return true;
   {
     DisallowHeapAllocation no_gc;
-    // During bootstrapping, callback functions are not enabled yet.
-    if (bootstrapper()->IsActive()) return true;
 
     if (receiver->IsJSGlobalProxy()) {
       Object* receiver_context =