Add forked version of femu_tests recipe.

Change-Id: I23176c6ec42da98e9ab3d0582b24c1faa96bd2f7
Bug: https://github.com/flutter/flutter/issues/63682
Reviewed-on: https://flutter-review.googlesource.com/c/recipes/+/5621
Reviewed-by: Keyong Han <keyonghan@google.com>
Commit-Queue: Godofredo Contreras <godofredoc@google.com>