Check support for each GL format independently.

Previous code tried to aggregate some checks, but therefore had several
subtle bugs. Make each format check independent. It's easier to check
whether it's correct by looking up the specs/extensions referenced and
tweak it if not.

Also removes some "workarounds" that were just working around our own
bugs in extension/version detection.

Also adds some more WebGL format functionality.

Also uses glTexStorage2D for formats that previously did not check for
support.

Use glTexStorage2D on Android/NVIDIA to work around N9 and Shield TV
issues with glTexImage2D.

Bug: chromium:1003481

Change-Id: Ie3295b1ca76a6068f1426e77783d9dc07698c56a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/243816
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
3 files changed