Fix a couple minor bugs in particle code

- Copy effect state to particle uniforms before each script, so changes
  from spawn or update are visible.
- Guard path binding against out of range access
- New effect that actually stresses both of these conditions

Change-Id: Ice6112793099e515438af8bb863e9e1bf03d08b1
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/249125
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
3 files changed