[Impeller] No-op builds on mac compile shaders over and over. #109257
Description
The following actions are taken on no-op builds.
[1/7] ACTION //flutter/lib/ui/fixtures/shaders/general_shaders:compile_general_shaders(//build/toolchain/mac:clang_x64)
[2/7] STAMP obj/flutter/lib/ui/fixtures/shaders/general_shaders/compile_general_shaders.stamp
[3/7] COPY 'gen/flutter/lib/ui/fixtures/shaders/general_shaders/iplr/functions%20with_space.frag.iplr' 'gen/flutter/lib/ui/assets/functions%20with_space.frag.iplr'
[4/7] STAMP obj/flutter/lib/ui/fixtures/shaders/general_shaders/_cf_fixtures.stamp
[5/7] STAMP obj/flutter/lib/ui/fixtures/shaders/general_shaders/fixtures.stamp
[6/7] STAMP obj/flutter/lib/ui/fixtures/shaders/general_shaders/general_shaders.stamp
[7/7] STAMP obj/flutter/lib/ui/fixtures/shaders/shaders.stamp