Add tests for Bitmap#eraseColor(@ColorLong)

Bug: 120904891
Test: This

Test for Exceptions, and verify that various ColorLongs end up with
roughly the same color returned by getPixel().

Also update ColorUtils#verifyColor to give better error messages.

Change-Id: I162451ebf807f3a8a44679e5c10406468c922500
2 files changed