Switch to float vertex colors for wide color vertex attribs

Bug: chromium:985500

Change-Id: Iab73405728dc64c816f736e95b00a23e11fd4888
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/258565
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
11 files changed