The fuzzer discovered that it could overflow the program-size value.
Rewrote the logic to use SkSafeMath everywhere, and to early-exit as
soon as a statement manages to exceed the program size.
Change-Id: I01511b2201173c95ebc1ac602901410ac9d74d73
Bug: oss-fuzz:38697
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/449098
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
