Reduce shared dependencies between liboslcomp and liboslexec #3842

Job	Run time
macos-13 C++17 py3.11 MacOS-13 llvm17	8m 42s
macos-14 C++17 py3.11 MacOS-14-ARM llvm17	4m 30s
Ubuntu Debug gcc7/C++17 llvm9 py3.7 oiio2.3 exr2.4 sse4 exr2.4	3m 44s
VFX2021 gcc9/C++17 llvm11 py3.7 oiio2.4 sse4 batch-b8avx2	7m 1s
Ubuntu gcc10/C++17 llvm10 oiio-release avx2	3m 47s
VFX2022 gcc9/C++17 llvm13 py3.9 exr3.1 oiio-rel avx2	6m 49s
Ubuntu latest releases gcc11/C++17 llvm17 exr3.2 py3.10 avx2 batch-b16avx512	10m 15s
VFX2022 clang12/C++17 llvm12 oiio-main py3.9 avx2 batch-avx512	5m 12s
Ubuntu latest releases +OIIO3 gcc11/C++17 llvm17 exr3.2 py3.10 avx2 batch-b16avx512	10m 33s
VFX2022 gcc9/C++17 llvm11 py3.9 exr3.1 oiio2.3 sse2 batch-b4sse2	6m 41s
Ubuntu bleeding edge gcc12/C++17 llvm17 oiio/ocio/exr/pybind-main py3.10 avx2 batch-b16avx512	5m 44s
VFX2022 icc/C++17 llvm14 py3.9 oiio-main avx2	17m 49s
Ubuntu clang14/C++17 llvm14 py3.8 avx2 batch-b16avx512	7m 19s
VFX2022 icx/C++17 llvm14 py3.9 oiio2.3 avx2	9m 6s
Ubuntu clang-format	2m 6s
VFX2023 gcc11/C++17 llvm15 py3.10 oiio-rel avx2	8m 12s
VFX2023 GPU Cuda11 gcc11/C++17 llvm15 py3.10 OIIO-main avx2	6m 43s
VFX2024 gcc11/C++17 llvm17 py3.11 boost1.82 oiio-rel avx2	8m 17s
VFX2021 oldest everything gcc9/C++17 llvm9 py3.7 oiio2.3 no-simd	5m 44s
VFX2022 sanitizers	7m 37s
VFX2023 abi check	13m 29s
	2h 39m 20s

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