Parallelize constraint group solving #226

Job	Run time
ubuntu (jammy, v6.14, linux/amd64,linux/arm64,linux/ppc64le,linux/s390x, OFF)	19m 6s
manylinux (min) (Dockerfile.manylinux_2_28_x86_64, quay.io/pypa/manylinux_2_28_x86_64, manylinux_...	39m 19s
ubuntu (noble, v6.14, linux/amd64,linux/arm64,linux/ppc64le,linux/s390x, OFF)	19m 17s
manylinux (min) (Dockerfile.manylinux_2_28_aarch64-min, quay.io/pypa/manylinux_2_28_aarch64, many...	2h 2m 9s
ubuntu (oracular, v6.14, linux/amd64,linux/arm64,linux/ppc64le,linux/s390x, OFF)	12m 20s
manylinux (min) (Dockerfile.manylinux_2_28_ppc64le-min, quay.io/pypa/manylinux_2_28_ppc64le, many...	1h 58m 6s
manylinux (min) (Dockerfile.manylinux_2_28_s390x-min, quay.io/pypa/manylinux_2_28_s390x, manylinu...	1h 58m 50s
tracy profiler (v6.14, ON)	15m 19s
manylinux (Dockerfile.manylinux_2_28_aarch64, jslee02/dart-dev:manylinux_2_28_aarch64-min-v6.14, ...	4h 33m 56s
manylinux (Dockerfile.manylinux_2_28_ppc64le, jslee02/dart-dev:manylinux_2_28_ppc64le-min-v6.14, ...	4h 27m 49s
manylinux (Dockerfile.manylinux_2_28_s390x, jslee02/dart-dev:manylinux_2_28_s390x-min-v6.14, many...	4h 21m 11s
	21h 7m 22s

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