[co19] LibTests/async tests enabled in status files

Change-Id: I268dff370f6067ebe7ede16b1e655a427329bca0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/155603
Reviewed-by: Alexander Thomas <[email protected]>

Author: sgrekhov

tests/co19/co19-co19.status

@@ -50,18 +50,6 @@ LanguageFeatures/Super-bounded-types/*: Skip # Not migrated to NNBD
 LanguageFeatures/Triple-Shift/*: Skip # Not migrated to NNBD
 LanguageFeatures/int-to-double/*: Skip # Not migrated to NNBD
 LanguageFeatures/regression/*: Skip # Not migrated to NNBD
-LibTest/async/Completer/*: Skip # Not migrated to NNBD
-LibTest/async/DeferredLibrary/*: Skip # Not migrated to NNBD
-LibTest/async/EventSink/*: Skip # Not migrated to NNBD
-LibTest/async/Future/*: Skip # Not migrated to NNBD
-LibTest/async/Stream/*: Skip # Not migrated to NNBD
-LibTest/async/StreamConsumer/*: Skip # Not migrated to NNBD
-LibTest/async/StreamController/*: Skip # Not migrated to NNBD
-LibTest/async/StreamIterator/*: Skip # Not migrated to NNBD
-LibTest/async/StreamSink/*: Skip # Not migrated to NNBD
-LibTest/async/StreamTransformer/*: Skip # Not migrated to NNBD
-LibTest/async/Timer/*: Skip # Not migrated to NNBD
-LibTest/async/Zone/*: Skip # Not migrated to NNBD
 LibTest/collection/DoubleLinkedQueue/*: Skip # Not migrated to NNBD
 LibTest/collection/DoubleLinkedQueueEntry/*: Skip # Not migrated to NNBD
 LibTest/collection/HasNextIterator/*: Skip # Not migrated to NNBD