Vulkan: Set fragment output locations in SPIR-V The shader translator outputs arbitrary location indices for fragment outputs. Once compiled by glslang, the SPIR-V transformer modifies these decorations. Bug: angleproject:3394 Change-Id: Ib9d8336bccc392e789e4d93031fdcce9c466b7a6 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2011214 Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Tim Van Patten <timvp@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org>