[dart2wasm] Remove experimental warning for `dart compile wasm` and make `dart compile --help` show the wasm subcommand

Closes https://github.com/dart-lang/sdk/issues/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

diff --git a/pkg/dart2wasm/lib/dart2wasm.dart b/pkg/dart2wasm/lib/dart2wasm.dart
index f4f2677..19b421c 100644
--- a/pkg/dart2wasm/lib/dart2wasm.dart
+++ b/pkg/dart2wasm/lib/dart2wasm.dart
@@ -124,9 +124,6 @@
   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

diff --git a/pkg/dartdev/lib/src/commands/compile.dart b/pkg/dartdev/lib/src/commands/compile.dart
index 34772de..bae371d 100644
--- a/pkg/dartdev/lib/src/commands/compile.dart
+++ b/pkg/dartdev/lib/src/commands/compile.dart
@@ -631,7 +631,7 @@
       .toList();
 
   CompileWasmCommand({bool verbose = false})
-      : super(commandName, help, verbose, hidden: !verbose) {
+      : super(commandName, help, verbose) {
     argParser
       ..addOption(
         outputFileOption.flag,