tweak error behavior for redeclared uniforms for vulkan-relaxed #287

Job	Run time
windows (windows-2019, windows, Debug)	10m 56s
macos (macos-11, osx, clang, clang++, Debug)	14m 17s
linux (ubuntu-20.04, linux, clang, clang++, Debug)	9m 29s
windows (windows-2019, windows, Release)	10m 39s
macos (macos-11, osx, clang, clang++, Release)	15m 13s
linux (ubuntu-20.04, linux, clang, clang++, Release)	10m 27s
linux (ubuntu-20.04, linux, gcc, g++, Debug)	12m 38s
linux (ubuntu-20.04, linux, gcc, g++, Release)	12m 59s
	1h 36m 38s

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