[ast] Flatten Wasm function names

Factory::NewFunction now requires names passed into it to be flat.
Make sure to flatten Wasm function names when creating new Wasm JS
functions.

Fixes: chromium:1047368
Change-Id: I7bd2d8bc83ae8fab901ab469872bce0f703fc3ec
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2030738
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66064}

src/wasm/wasm-objects.cc

@@ -1846,6 +1846,7 @@ Handle<WasmJSFunction> WasmJSFunction::New(Isolate* isolate,
   Handle<String> name = isolate->factory()->Function_string();
   if (callable->IsJSFunction()) {
     name = JSFunction::GetName(Handle<JSFunction>::cast(callable));
+    name = String::Flatten(isolate, name);
   }
   Handle<Map> function_map = isolate->wasm_exported_function_map();
   NewFunctionArgs args =

test/mjsunit/mjsunit.status

@@ -306,6 +306,7 @@
   'regress/regress-crbug-772056': [SKIP],
   'regress/regress-crbug-816961': [SKIP],
   'regress/regress-crbug-969498': [SKIP],
+  'regress/regress-crbug-1047368': [SKIP],
   'regress/wasm/*': [SKIP],
   'regress/regress-8947': [SKIP],
   'regress/regress-9165': [SKIP],

test/mjsunit/regress/regress-crbug-1047368.js

+// Copyright 2020 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// Flags: --wasm-staging
+
+new WebAssembly.Function({
+    parameters: [],
+    results: []
+  }, x => x);
+const long_variable = {
+  toString: () => {
+  }
+};