We are currently calling onImageRenderPassWrite() on the read render
target within resolveColorWithSubpass(). We need to instead call
onColorDraw() on the draw render target, since that's what's actually
being written.

Bug: b/159903491
Test: CQ
Change-Id: I577381d91228e132950455d2e872fbb9b066d0c8
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2458850Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Charlie Lao <cclao@google.com>
Commit-Queue: Tim Van Patten <timvp@google.com>