Allows the following semantics:
- If the disable flag is passed, never check
- If we're in non-sound mode, never check to avoid a breaking
change (this was the behavior before)
- If the enable flag was passed and we're in sound mode,
always check
- If we're in sound mode and with >= -03, don't check
Discussion in https://github.com/dart-lang/sdk/issues/50710
Change-Id: If83aaebb2745e4c8bcaa3f5a38ff41d79a869b8b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/289451
Reviewed-by: Nicholas Shahan <nshahan@google.com>
Commit-Queue: Srujan Gaddam <srujzs@google.com>