Add program-too-large test using for loops without blocks.

The fuzzer has discovered a bug in our program size-checking logic; for
loops that immediately contain another for loop (with no block) were not
counting the inner loop's iterations. This allowed it to exceed our
maximum program-size threshold (and time out during SkVM compilation).

This test demonstrates the issue. A followup will fix it.

Change-Id: I3b7d4c8a4f0ed04cf0aba3f1a32fdad7d6d784e7
Bug: oss-fuzz:37837
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/449096
Commit-Queue: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
6 files changed