Add egl config support GL_RGB10_A2 for Linux Headless This patch add egl config support GL_RGB10_A2 for Linux Headless, optionally add GL_RGB10_A2 after checking it's renderable. Bug: angleproject:377349381 Change-Id: I16943c74161d18399040fcbe2f1c7a80988dac8a Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6021860 Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Charlie Lao <cclao@google.com>