test: wait for message from parent in embedding cctest

I’ve seen this fail a few times in CI, presumably because the inspector commmand did not reach the child thread in time. Explicitly waiting seems to solve that. Refs: #30467 Backport-PR-URL: #35241 PR-URL: #32563 Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: James M Snell <[email protected]>

Author: addaleax

test/cctest/test_environment.cc

@@ -406,6 +406,7 @@ TEST_F(EnvironmentTest, InspectorMultipleEmbeddedEnvironments){
 
  v8::Local<v8::Value> extracted_value = LoadEnvironment(
  environment,
+"while (!global.variableFromParent){}\n"
 "return global.variableFromParent;",
 std::move(data->inspector_parent_handle)).ToLocalChecked();