Move the RoundUp() and IsPowerOfTwo() methods from Resolver.cc to this file.
Add tests
Change-Id: Ib7af53dfa5e69083ec4fc2484da92a84c9468818
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/44682
Auto-Submit: Ben Clayton <bclayton@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>