Don't set the context in Push...Context runtime functions

The Isolate::context field doesn't track the context while JS is
executing. It's updated at boundary sites when entering runtime
through CEntry or returning to runtime in Invoke(). These set_context
calls are unnecessary.

Bug: v8:8888
Change-Id: Ifb9818b47699d2b1b37ebf0c19c2caf59fd17427
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2247772
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68380}

src/runtime/runtime-scopes.cc

@@ -612,40 +612,35 @@ RUNTIME_FUNCTION(Runtime_NewFunctionContext) {
   return *isolate->factory()->NewFunctionContext(outer, scope_info);
 }
 
+// TODO(jgruber): Rename these functions to 'New...Context'.
 RUNTIME_FUNCTION(Runtime_PushWithContext) {
   HandleScope scope(isolate);
   DCHECK_EQ(2, args.length());
   CONVERT_ARG_HANDLE_CHECKED(JSReceiver, extension_object, 0);
   CONVERT_ARG_HANDLE_CHECKED(ScopeInfo, scope_info, 1);
   Handle<Context> current(isolate->context(), isolate);
-  Handle<Context> context =
-      isolate->factory()->NewWithContext(current, scope_info, extension_object);
-  isolate->set_context(*context);
-  return *context;
+  return *isolate->factory()->NewWithContext(current, scope_info,
+                                             extension_object);
 }
 
+// TODO(jgruber): Rename these functions to 'New...Context'.
 RUNTIME_FUNCTION(Runtime_PushCatchContext) {
   HandleScope scope(isolate);
   DCHECK_EQ(2, args.length());
   CONVERT_ARG_HANDLE_CHECKED(Object, thrown_object, 0);
   CONVERT_ARG_HANDLE_CHECKED(ScopeInfo, scope_info, 1);
   Handle<Context> current(isolate->context(), isolate);
-  Handle<Context> context =
-      isolate->factory()->NewCatchContext(current, scope_info, thrown_object);
-  isolate->set_context(*context);
-  return *context;
+  return *isolate->factory()->NewCatchContext(current, scope_info,
+                                              thrown_object);
 }
 
-
+// TODO(jgruber): Rename these functions to 'New...Context'.
 RUNTIME_FUNCTION(Runtime_PushBlockContext) {
   HandleScope scope(isolate);
   DCHECK_EQ(1, args.length());
   CONVERT_ARG_HANDLE_CHECKED(ScopeInfo, scope_info, 0);
   Handle<Context> current(isolate->context(), isolate);
-  Handle<Context> context =
-      isolate->factory()->NewBlockContext(current, scope_info);
-  isolate->set_context(*context);
-  return *context;
+  return *isolate->factory()->NewBlockContext(current, scope_info);
 }