[ Dart CLI ] Fix issue where -D was not being accepted by 'dart run'

Fixes #43779

Fixed: 43779
Change-Id: I886db8014cc3ea1f870974a21a552d7983b6b408
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/167700
Reviewed-by: Ryan Macnak <[email protected]>
Commit-Queue: Ben Konyi <[email protected]>

Author: bkonyi

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

@@ -104,6 +104,8 @@ class RunCommand extends DartdevCommand<int> {
         );
     }
     argParser
+      ..addMultiOption('define',
+          abbr: 'D', help: 'Defines an environment variable', hide: true)
       ..addFlag(
         'disable-service-auth-codes',
         hide: !verbose,

pkg/dartdev/test/commands/run_test.dart

@@ -154,6 +154,7 @@ void run() {
       '--no-pause-isolates-on-start',
       '--no-pause-isolates-on-exit',
       '--no-pause-isolates-on-unhandled-exceptions',
+      '-Dfoo=bar',
       p.relativeFilePath,
     ]);
     expect(
@@ -173,6 +174,7 @@ void run() {
       '--no-pause-isolates-on-exit',
       '--no-pause-isolates-on-unhandled-exceptions',
       '--disable-service-auth-codes',
+      '-Dfoo=bar',
       p.relativeFilePath,
     ]);