Attempt at themed CI targets re-organisation #2128

Job	Run time
aarch64 (clang, aarch64_osx)	21m 23s
externals (clang, x86, -msse2)	44m 57s
msvc (Debug, -DEVE_NO_FORCEINLINE)	2m 31s
externals (gcc, x86, -msse2)	51m 10s
generic-x86 (clang, x86, -DEVE_NO_SIMD, -DEVE_USE_PCH=ON)	16m 28s
extra-x86 (clang, x86, -march=skylake-avx512)	37m 45s
generic-x86 (clang, x86, -msse2, -DEVE_USE_PCH=OFF)	23m 2s
extra-x86 (gcc, x86, -march=skylake-avx512)	1h 6m 3s
riscv (clang, riscv, -mrvv-vector-bits=128)	7m 9s
generic-x86 (clang, x86, -msse4.2, -DEVE_USE_PCH=ON)	17m 8s
special-arch (clang, arm, -Wno-psabi)	37m 9s
extra-x86 (clang_libcpp, x86, -msse2)	23m 26s
generic-x86 (clang, x86, -mavx, -DEVE_USE_PCH=ON)	23m 34s
special-arch (gcc, ppc64, -Wno-psabi)	43m 4s
extra-x86 (clang, x86, -mavx2 -mbmi2 -DEVE_USE_BMI_ON_AVX2)	30m 8s
generic-x86 (clang, x86, -mavx2, -DEVE_USE_PCH=ON)	22m 56s
special-arch (gcc, sve256, -Wno-psabi)	51m 56s
extra-x86 (gcc, x86, -mavx2 -mbmi2 -DEVE_USE_BMI_ON_AVX2)	52m 17s
generic-x86 (gcc, x86, -DEVE_NO_SIMD, -DEVE_USE_PCH=ON)	20m 57s
special-arch (gcc, sve512, -Wno-psabi)	1h 45m 56s
generic-x86 (gcc, x86, -msse2, -DEVE_USE_PCH=OFF)	26m 10s
generic-x86 (gcc, x86, -msse4.2, -DEVE_USE_PCH=ON)	22m 50s
generic-x86 (gcc, x86, -mavx, -DEVE_USE_PCH=ON)	30m 14s
generic-x86 (gcc, x86, -mavx2, -DEVE_USE_PCH=ON)	29m 4s
	13h 27m 17s

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