Vulkan: Add test for FBO with unequal sized attachments Before OpenGLES3.0, framebuffer object with unequal sized attachment is considered incomplete. That restriction has been removed in ARB version of spec and is legit use in OpenGLES 3.0. This adds a test for this specific usage. Bug: b/181800403 Test: FramebufferTest_ES3.AttachmentWithUnequalDimensions Change-Id: I79608bfd8f10855c6fc47511e080ba3ca4e46c59 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2824366 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Tim Van Patten <timvp@google.com> Commit-Queue: Charlie Lao <cclao@google.com>