GPUUploadManagerImpl::Page: support persistent mapping #4127

Job	Run time
Linux -> Pre-checks	23s
Linux -> GCC-x64, Debug	12m 32s
Linux -> GCC-x64, Release	10m 35s
Linux -> Clang-NO_GLSLANG-NO_HLSL-x64, Release	6m 39s
Linux -> Clang-x64, Debug	10m 37s
Linux -> Clang-NO_GLSLANG-x64, Debug	8m 11s
Linux -> Clang-x64, Release	12m 8s
	1h 1m 5s

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