RISCV64-CI: don't rely on dependency resolution for qemu-user #6269

Job	Run time
build (ubuntu-latest, gfortran, cmake)	45m 35s
build (ubuntu-latest, flang, cmake)	9m 23s
cross_build (mips64el, mips64el-linux-gnuabi64, DYNAMIC_ARCH=1 TARGET=GENERIC)	3m 42s
neoverse_build	7m 52s
cross_build (alpha, alpha-linux-gnu, TARGET=EV4)	2m 41s
build (ubuntu-latest, flang, make)	4m 58s
cross_build (mipsel, mipsel-linux-gnu, TARGET=MIPS1004K)	3m 39s
build (macos-latest, gfortran, cmake)	16m 2s
build (macos-latest, gfortran, make)	4m 52s
cross_build (riscv64, riscv64-linux-gnu, TARGET=RISCV64_GENERIC)	2m 37s
msys2 (UCRT64, int64, Release)	15m 23s
build (ubuntu-latest, gfortran, make)	21m 56s
msys2 (UCRT64, int32, Release)	16m 44s
msys2 (MINGW32, int32, Release)	15m 52s
msys2 (CLANG64, int32, Release)	18m 6s
msys2 (CLANG64, int64, Release)	18m 3s
msys2 (UCRT64, int32, None, mingw-w64-ucrt-x86_64, fc)	13m 20s
	3h 40m 45s

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