bcfe26cba0
The many different entrypoints to the CFE have repeatedly shown problems with targets that do not support unevaluated constants being used without providing an environment. Making the targets opt-in to supporting unevaluated constants will give the users of CFE early notice that CFE is used inconsistently (as opposed to the backends failing when they happen to see an UnevaluatedConstant node that they don't support). Change-Id: I98c80df3a551823598e413e2895f5649f22f7c22 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/110561 Reviewed-by: Vijay Menon <vsm@google.com> Commit-Queue: Johnni Winther <johnniwinther@google.com>