Use Contains instead of IndexOf. #936

Job	Run time
MacOS (Q8/Q16/Q16-HDRI)	2m 55s
Linux (Q8/Q16/Q16-HDRI, x64)	4m 14s
Linux musl (Q8/Q16/Q16-HDRI, x64)	5m 30s
Library (Core)	6m 32s
MacOS (Q8/Q16/Q16-HDRI, arm64)	2m 1s
Library (SystemDrawing)	6m 35s
Windows (Q8, x86)	6m 44s
Library (SystemWindowsMedia)	7m 1s
Windows (Q8, x64)	8m 9s
Windows (Q8, arm64)	6m 44s
Windows (Q8, Any CPU)	6m 33s
Windows (Q8-OpenMP, x64)	9m 12s
Windows (Q8-OpenMP, arm64)	7m 54s
Windows (Q16, x86)	9m 17s
Windows (Q16, x64)	9m 23s
Windows (Q16, arm64)	7m 42s
Windows (Q16, Any CPU)	8m 46s
Windows (Q16-OpenMP, x64)	8m 11s
Windows (Q16-OpenMP, arm64)	6m 21s
Windows (Q16-HDRI, x86)	8m 42s
Windows (Q16-HDRI, x64)	9m 25s
Windows (Q16-HDRI, arm64)	8m 54s
Windows (Q16-HDRI, Any CPU)	8m 45s
Windows (Q16-HDRI-OpenMP, x64)	6m 29s
Windows (Q16-HDRI-OpenMP, arm64)	6m 36s
	2h 58m 35s

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