Fix invalidation of GL_FRAMEBUFFER invalidating READ FBO Per spec, GL_FRAMEBUFFER means GL_DRAW_FRAMEBUFFER for glInvalidateFramebuffer. Bug: chromium:1267424 Change-Id: I8c9ab61ecdbd4ccee4262dc8559b2feb02b4837c Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3266176 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>