[promises] Add %WaitForPromise runtime call to allow tests to reliably wait for promises to be fini…

src/runtime/runtime-test.cc

 // Copyright 2014 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.
 
 #include "src/runtime/runtime-utils.h"
 
 #include <memory>
 
 #include "src/arguments.h"
 #include "src/assembler-inl.h"
@@ skipping 930 matching lines @@
   HandleScope scope(isolate);
   CONVERT_ARG_HANDLE_CHECKED(JSObject, instance_obj, 0);
   CHECK(WasmInstanceObject::IsWasmInstanceObject(*instance_obj));
   Handle<WasmInstanceObject> instance =
       Handle<WasmInstanceObject>::cast(instance_obj);
   if (!instance->has_debug_info()) return 0;
   uint64_t num = instance->debug_info()->NumInterpretedCalls();
   return *isolate->factory()->NewNumberFromSize(static_cast<size_t>(num));
 }
 
+RUNTIME_FUNCTION(Runtime_IncrementWaitCount) {
+  isolate->IncrementWaitCountForTesting();
+  return isolate->heap()->undefined_value();
+}
+
+RUNTIME_FUNCTION(Runtime_DecrementWaitCount) {
+  isolate->DecrementWaitCountForTesting();
+  return isolate->heap()->undefined_value();
+}
 }  // namespace internal
 }  // namespace v8