[vm] Deoptimize code if can-be-Future property of a class changes due to dynamic loading

Sometimes compiler omits type checks for the 'await' and 'return from
async' by relying on the fact that certain classes cannot hold
instances of Future.

In JIT mode, the property 'class-can-be-Future' may change when a new
class is loaded dynamically (e.g. through IsolateMirror.loadUri).

In such a case, the generated code assuming that certain class
cannot be Future should be correctly deoptimized.
This CL implements this deoptimization by adding such classes into
the list of CHA guarded classes.

TEST=runtime/tests/vm/dart/await_type_check_with_dynamic_loading_test.dart

Change-Id: Ib3a3768d073e8562b794186e72cb9d61e9f496fa
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/309822
Reviewed-by: Martin Kustermann <kustermann@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>