D3D11: Skip blits if there is no intersection of dest areas Blit11 would clip the destination rectangle with the destination size but ignore the result. gl::ClipRectangle returns false when the rectangles do not intersect at all, indicating the blit can be skipped. This could lead to an out-of-bounds write to the GPU memory for the destination texture. Mark ClipRectangle as nodiscard to prevent future issues. Bug: chromium:1199402 Change-Id: I260e82d0917b8aa7e7887f2c9f7ed4b1a03ba785 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2836786 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Geoff Lang <geofflang@chromium.org>