Note: minimum buffer size is now checked for texture parameters in
GLES2.

- Mipmap generation hint
- Crop rect
- Update test expectations

BUG=angleproject:2306

Change-Id: Ib459b8191111732a1326b44f2226b72ca297325a
Reviewed-on: https://chromium-review.googlesource.com/1111575Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Lingfeng Yang <lfy@google.com>