Vulkan: Bugfix in SPIRV entrypoint transformation Perform varying precision fixer transformation before other shader-stage-specific transforms that could potentially modify the interfaceList. Also enhance EXTBlendFuncExtendedDrawTest by enabling additional config with VaryingsRequireMatchingPrecisionInSpirv feature enabled Bug: angleproject:386749841 Change-Id: Ife4a2f932415296f1565527e50a2b8646cd7697d Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6207741 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: mohan maiya <m.maiya@samsung.com>