This uses the information from the static types now used in inference which
can improve the precision in particular for generic classes. Since type
masks lose the type argument information, we cannot expect locating members
based on the type mask to be more precise than what has been found through
the static types.
This CL also expands the unit test framework to support unit test of
optimizations and the emission model, including tests of the improved
field access handling.
Closes#35433
Change-Id: Ia5de15efaf8b60c8723943bb34de6eec7d380798
Reviewed-on: https://dart-review.googlesource.com/c/88440
Reviewed-by: Stephen Adams <sra@google.com>