feat: busybox glibc test support
Resolved merge conflicts locally. Verified: make all FS_IMG=sdcard-rv.img TOOLPREFIX=riscv64-unknown-elf- timeout 1800s make qemu FS_IMG=sdcard-rv.img TOOLPREFIX=riscv64-unknown-elf- > qemu.log 2>&1
Resolved merge conflicts locally. Verified: make all FS_IMG=sdcard-rv.img TOOLPREFIX=riscv64-unknown-elf- timeout 1800s make qemu FS_IMG=sdcard-rv.img TOOLPREFIX=riscv64-unknown-elf- > qemu.log 2>&1