async llvm compile, take 2

This version has fewer uninitentional sync points.

Turning on stats, looks like roughly 93% of calls
go through the JIT, the rest the interpreter.  When
synchronous 100% go through the JIT, of course.

No diffs now that we've made the interpreter and JIT
guarantee consistent math.

Change-Id: Id58c860809970f78773b2ae7f40b3ea091b38440
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/275011
Commit-Queue: Mike Klein <mtklein@google.com>
Commit-Queue: Herb Derby <herb@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2 files changed