Add unit test for Type::minimumValue and Type::maximumValue.

This test confirms that our logic to derive the min and max value of a
given integer type actually matches reality.

Change-Id: I1cb5fba6bfb9ffdcf4972d8feed79cf71e11d0ca
Bug: skia:10932
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/413376
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>
2 files changed