Introduce a blendop & masks hash #864

Job	Run time
Win64.UCRT64.skiptest.Debug.Ninja	22m 33s
Win64.UCRT64.nofeatures.Debug.Ninja	21m 11s
Win64.UCRT64.skiptest.Release.Ninja	22m 28s
Linux.noble.GNU14.skiptest.Debug.Ninja	5m 10s
Win64.UCRT64.nofeatures.Release.Ninja	21m 45s
macOS.${{ matrix.compiler.compiler }}.${{ matrix.build.xcode }}.${{ matrix.target }}.${{ matrix.btype }}.${{ matrix.generator }}	0s
Linux.noble.GNU14.nofeatures.Debug.Ninja	4m 1s
Linux.noble.GNU14.skiptest.Release.Ninja	6m 3s
Linux.noble.GNU14.nofeatures.Release.Ninja	4m 50s
Linux.noble.LLVM16.skiptest.Debug.Ninja	5m 20s
Linux.noble.LLVM16.nofeatures.Debug.Ninja	4m 43s
Linux.noble.LLVM16.skiptest.Release.Ninja	6m 44s
Linux.noble.LLVM16.nofeatures.Release.Ninja	5m 28s
	2h 10m 16s

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