D3D11: cleanup around inline constants #4041

Job	Run time
Linux -> Pre-checks	16s
Linux -> Clang-NO_GLSLANG-NO_HLSL-x64, Release	6m 33s
Linux -> GCC-x64, Debug	12m 20s
Linux -> Clang-x64, Release	10m 56s
Linux -> Clang-NO_GLSLANG-x64, Debug	8m 4s
Linux -> Clang-x64, Debug	13m 51s
Linux -> GCC-x64, Release	11m 4s
	1h 3m 4s

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