simplify skvm tests using allow_jit

We can of course use allow_jit to test with and without JIT!

This testing was the only reason Program::dropJIT() was public.  Given
how tricky its implementation is, I'd rather keep it a private detail
than exposed API, in case one day we find need to make it impossible.

Change-Id: Ifa256355309d9baf1bae506d75951381dce9b53c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/367896
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
2 files changed