RISCV64-CI: don't rely on dependency resolution for qemu-user #6219

Job	Run time
neoverse_build	7m 58s
msys2 (UCRT64, int64, Release)	15m 0s
msys2 (MINGW32, int32, Release)	16m 4s
msys2 (UCRT64, int32, Release)	14m 22s
msys2 (CLANG64, int64, Release)	18m 3s
msys2 (CLANG64, int32, Release)	18m 47s
cross_build (alpha, alpha-linux-gnu, TARGET=EV4)	3m 2s
build (ubuntu-latest, gfortran, cmake)	44m 47s
cross_build (riscv64, riscv64-linux-gnu, TARGET=RISCV64_GENERIC)	2m 43s
build (macos-latest, gfortran, cmake)	35m 51s
cross_build (mips64el, mips64el-linux-gnuabi64, DYNAMIC_ARCH=1 TARGET=GENERIC)	3m 45s
build (macos-latest, gfortran, make)	11m 9s
build (ubuntu-latest, gfortran, make)	22m 29s
build (ubuntu-latest, flang, make)	6m 56s
build (ubuntu-latest, flang, cmake)	12m 19s
cross_build (mipsel, mipsel-linux-gnu, TARGET=MIPS1004K)	3m 27s
msys2 (UCRT64, int32, None, mingw-w64-ucrt-x86_64, fc)	12m 53s
	4h 9m 35s

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