[vm/fuzzer] add --enable-asserts to AOT step
[vm/fuzzer] add --enable-asserts to AOT step

Rationale:
This exposes certain bugs in a cleaner way
than just crashing. See bug for an example.

https://github.com/dart-lang/sdk/issues/38965
https://github.com/dart-lang/sdk/issues/38979

Change-Id: Ib6ce52e31d5ca539fb4aedab989638949751627f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/122168
Reviewed-by: Alexander Markov <239e774fd29abc1267878f57afe1a8a03e0ca887@google.com>
Commit-Queue: Aart Bik <293afa0533434225484ba3f9bf2859340baba6ea@google.com>

dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk