Migrate js_util_test to async_minitest
Migrate js_util_test to async_minitest

Change-Id: I9b232f7a093107df93b8fd4a62c29a70f206a550
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/139826
Reviewed-by: Bob Nystrom <afede3a9ebedb865bee78398feff6fbe97068f17@google.com>
Commit-Queue: Srujan Gaddam <4175f2f2dd3cde6c8ffb10fc9674dc09abf813fe@google.com>

dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk