[dart2wasm] Remove experimental warning for dart compile wasm and m…

…ake `dart compile --help` show the wasm subcommand

Closes #32894

Change-Id: Ief15c21bb28de8df6ef9aefbb8891d9af9368626
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/368307
Reviewed-by: Ömer Ağacan <omersa@google.com>
Reviewed-by: Michael Thomsen <mit@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>

pkg/dart2wasm/lib/dart2wasm.dart

@@ -124,9 +124,6 @@ WasmCompilerOptions parseArguments(List<String> arguments) {
   Never usage() {
     print("Usage: dart2wasm [<options>] <infile.dart> <outfile.wasm>");
     print("");
-    print("*NOTE*: Wasm compilation is experimental.");
-    print("The support may change, or be removed, with no advance notice.");
-    print("");
     print("Options:");
     for (String line in parser.usage.split('\n')) {
       print('\t$line');

pkg/dartdev/lib/src/commands/compile.dart

@@ -631,7 +631,7 @@ class CompileWasmCommand extends CompileSubcommandCommand {
       .toList();
 
   CompileWasmCommand({bool verbose = false})
-      : super(commandName, help, verbose, hidden: !verbose) {
+      : super(commandName, help, verbose) {
     argParser
       ..addOption(
         outputFileOption.flag,