Fix some hyperthreading errors. #5834

Job	Run time
msys2 (UCRT64, int64, Release)	13m 22s
neoverse_build	8m 16s
msys2 (UCRT64, int32, Release)	14m 36s
msys2 (CLANG64, int32, Release)	16m 47s
msys2 (MINGW32, int32, Release)	14m 58s
msys2 (UCRT64, int32, None, mingw-w64-ucrt-x86_64, fc)	12m 37s
msys2 (CLANG64, int64, Release)	15m 57s
build (macos-latest, gfortran, make)	11m 54s
build (macos-latest, gfortran, cmake)	25m 12s
build (ubuntu-latest, flang, make)	16m 16s
build (ubuntu-latest, gfortran, cmake)	46m 12s
build (ubuntu-latest, gfortran, make)	22m 13s
build (ubuntu-latest, flang, cmake)	45m 36s
cross_build (riscv64, riscv64-linux-gnu, TARGET=RISCV64_GENERIC)	6m 26s
cross_build (mips64el, mips64el-linux-gnuabi64, DYNAMIC_ARCH=1 TARGET=GENERIC)	7m 59s
cross_build (alpha, alpha-linux-gnu, TARGET=EV4)	5m 57s
cross_build (mipsel, mipsel-linux-gnu, TARGET=MIPS1004K)	7m 2s
	4h 51m 20s

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