[VM/nnbd] Do not apply legacy erasure to type literals.
[VM/nnbd] Do not apply legacy erasure to type literals.

See issue #42262.

Change-Id: I326eff8ca836c345caab266f5d27991b251e77ba
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/151020
Reviewed-by: Alexander Markov <239e774fd29abc1267878f57afe1a8a03e0ca887@google.com>
Commit-Queue: Régis Crelier <c2bf536a10d9f2530c38e4e8da517718be8c39ce@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