* Fix .dart test which didn't exersize the shared stub going into
runtime.
* Fix AllocateMint runtime entry int constant choice so it
doesn't fit a Smi on all targets, not only 32-bit ones.
* Make MintAllocation stubs go to runtime when
FLAG_shared_slow_path_triggers_gc is set for testing purposes.
Change-Id: I699f36c70d055af7bd17a16f81b92b9e9d87580c
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/129703
Reviewed-by: Martin Kustermann <kustermann@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
Artem Serov