Capture/Replay: Fix GetTexImage on Luminance GetTexImageANGLE and GetRenderbufferImageANGLE use ReadPixels to pull texture data. Luminance is not a renderable format, so it is not supported by ReadPixels. To support this, override Luminance formats to their underlying internal format. Test: angle_end2end_test --gtest_filter="*GetTexImage*" Bug: b/160014453 Bug: angleproject:4058 Change-Id: Id19344c2e2c06386a871338833e35b7747cb966b Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2321740 Reviewed-by: Manh Nguyen <nguyenmh@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Cody Northrop <cnorthrop@google.com>