Use generic kernels for SCAL on POWER4/POWER5 to fix corner cases of Inf/NAN #6100

Job	Run time
neoverse_build	7m 46s
build (ubuntu-latest, gfortran, make)	24m 5s
build (ubuntu-latest, flang, make)	17m 43s
build (ubuntu-latest, gfortran, cmake)	46m 11s
build (macos-latest, gfortran, make)	14m 18s
build (ubuntu-latest, flang, cmake)	47m 12s
build (macos-latest, gfortran, cmake)	47m 16s
cross_build (mips64el, mips64el-linux-gnuabi64, DYNAMIC_ARCH=1 TARGET=GENERIC)	3m 30s
cross_build (mipsel, mipsel-linux-gnu, TARGET=MIPS1004K)	3m 35s
cross_build (riscv64, riscv64-linux-gnu, TARGET=RISCV64_GENERIC)	2m 42s
cross_build (alpha, alpha-linux-gnu, TARGET=EV4)	3m 32s
msys2 (CLANG64, int32, Release)	18m 25s
msys2 (MINGW32, int32, Release)	16m 29s
msys2 (UCRT64, int32, None, mingw-w64-ucrt-x86_64, fc)	15m 6s
msys2 (UCRT64, int64, Release)	17m 26s
msys2 (UCRT64, int32, Release)	14m 50s
msys2 (CLANG64, int64, Release)	18m 5s
	5h 18m 11s

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