This achieves consistency with similar getters in the API.
This is technically a breaking change, since it changes a published
part of the Kernel API. Since the constants API is relatively new and
so far only used internally in the AOT compiler, the change is
expected to be unproblematic.
Closes https://github.com/dart-lang/sdk/issues/35696
Change-Id: I3ca30922580d226ccbdb6f77496983c21ef2102b
Reviewed-on: https://dart-review.googlesource.com/c/90220
Commit-Queue: Aske Simon Christensen <askesc@google.com>
Reviewed-by: Kevin Millikin <kmillikin@google.com>