esm: graduate top-level-await to stable

Removes the experimental label in the docs and makes the
`--experimental-top-level-await` flag a no-op.

V8 has removed the harmony flag in V8 9.1 and consider the feature
stable, there's no reason to keep it experimental in Node.js.

PR-URL: #42875
Reviewed-By: Jacob Smith <jacob@frende.me>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Mohammed Keyvanzadeh <mohammadkeyvanzade94@gmail.com>
Reviewed-By: Mestery <mestery@protonmail.com>
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>

Author: aduh95

doc/api/esm.md

@@ -556,8 +556,6 @@ would provide the exports interface for the instantiation of `module.wasm`.
 added: v14.8.0
 -->
 
-> Stability: 1 - Experimental
-
 The `await` keyword may be used in the top level body of an ECMAScript module.
 
 Assuming an `a.mjs` with

src/module_wrap.cc

@@ -429,13 +429,7 @@ void ModuleWrap::Evaluate(const FunctionCallbackInfo<Value>& args) {
     return;
   }
 
-  // If TLA is enabled, `result` is the evaluation's promise.
-  // Otherwise, `result` is the last evaluated value of the module,
-  // which could be a promise, which would result in it being incorrectly
-  // unwrapped when the higher level code awaits the evaluation.
-  if (env->isolate_data()->options()->experimental_top_level_await) {
-    args.GetReturnValue().Set(result.ToLocalChecked());
-  }
+  args.GetReturnValue().Set(result.ToLocalChecked());
 }
 
 void ModuleWrap::GetNamespace(const FunctionCallbackInfo<Value>& args) {

src/node_options.cc

@@ -670,14 +670,8 @@ PerIsolateOptionsParser::PerIsolateOptionsParser(
             kAllowedInEnvironment);
   Implies("--report-signal", "--report-on-signal");
 
-  AddOption("--experimental-top-level-await",
-            "",
-            &PerIsolateOptions::experimental_top_level_await,
-            kAllowedInEnvironment);
-  AddOption("--harmony-top-level-await", "", V8Option{});
-  Implies("--experimental-top-level-await", "--harmony-top-level-await");
-  Implies("--harmony-top-level-await", "--experimental-top-level-await");
-  ImpliesNot("--no-harmony-top-level-await", "--experimental-top-level-await");
+  AddOption(
+      "--experimental-top-level-await", "", NoOp{}, kAllowedInEnvironment);
 
   Insert(eop, &PerIsolateOptions::get_per_env_options);
 }

src/node_options.h

@@ -199,7 +199,6 @@ class PerIsolateOptions : public Options {
   bool node_snapshot = true;
   bool report_uncaught_exception = false;
   bool report_on_signal = false;
-  bool experimental_top_level_await = true;
   std::string report_signal = "SIGUSR2";
   inline EnvironmentOptions* get_per_env_options();
   void CheckOptions(std::vector<std::string>* errors) override;