Add a vk feature flag to only enable precision match fixer on IMG According to https://gitlab.khronos.org/vulkan/vulkan/-/merge_requests/5273, RelaxedPrecision does not need to match in the interface matching rules. However, removing the precision match is causing triangle clipping issues on IMG hardware. This change adds a feature flag to only run the code path that applies precision match in SpirV if the hardware is IMG. This is a follow-up change to https://crrev.com/c/4049421. Instead of adding back the code path that handles varying precision mismatch for every hardware, only enabling the code path if the vendor is IMG. Test: On Pixel6: $ adb shell setprop debug.angle.feature_overrides_enabled varyingsRequireMatchingPrecisionInSpirv $ out/AndroidDebug/angle_end2end_tests --gtest_filter="GLSLTest_ES3.MismatchPrecision*" --verbose Bug: angleproject:7488 Change-Id: Ia0155f14d523195df2f47b852ed6642918270e2a Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4054100 Commit-Queue: Yuxin Hu <yuxinhu@google.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Cody Northrop <cnorthrop@google.com>