Reland "Don't keep a non-msaa FBO with EXT_multisampled_render_to_texture"

This is a reland of I060988c63edbfeb628d5a6c34cda3e159066114a

Original change's description:
> Don't keep a non-msaa FBO with EXT_multisampled_render_to_texture
>
> This seems to cause bugs on various platforms. Instead, do the same
> thing we do for dmsaa: reconfigure a single FBO as msaa or not,
> based on need.
>
> Bug: chromium:1222095
> Change-Id: I4ca4aff32772ee2a9607c92c586ae9494f955229
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/442565
> Commit-Queue: Jim Van Verth <jvanverth@google.com>
> Reviewed-by: Brian Salomon <bsalomon@google.com>

Change-Id: I0bb9e9178170da391be0a295758879994bf4be0d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/452724
Reviewed-by: Chris Dalton <csmartdalton@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
4 files changed