Tighten the workaround for B5G6R5 on Intel drivers This driver bug has been fixed in 20.19.15.4539. BUG=chromium:644610 TEST=dEQP-GLES3.functional.fbo.blit.default_framebuffer.rgb565* Change-Id: I37556304ed4f70771fb88b792c01b6be5b3aa294 Reviewed-on: https://chromium-review.googlesource.com/424103 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>