Delete Gr testing contexts in reverse order

This fixes issues where we create a child shared context and expect work
on that to finish before deleting the parent.

Bug: skia:
Change-Id: Iab41b22026cd4b9ec1b9d74e7841ee5051df6036
Reviewed-on: https://skia-review.googlesource.com/94962
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
1 file changed