add int3, vptest, jc

Will use these to implement assert_true on x86.

Change-Id: I9d2595a35518b6971dd8e418b583febd3960c7f6
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/253896
Commit-Queue: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Reed <reed@google.com>
Auto-Submit: Mike Klein <mtklein@google.com>
Reviewed-by: Mike Reed <reed@google.com>
3 files changed