`--real-source` option not working because of the change of toolchains.bootlin.com

[StarDuster]

As we can see there's no such path "test-system" directory under https://toolchains.bootlin.com/downloads/releases/toolchains/{arch}/, such as https://toolchains.bootlin.com/downloads/releases/toolchains/mips32/test-system is 404,

arm_now/arm_now/download.py

Line 39 in 7251c24

url = "https://toolchains.bootlin.com/downloads/releases/toolchains/{arch}/test-system/".format(arch=arch)

so arm_now install with --real-source will always fail with "ERROR: couldn't download files for this arch"

I browsed the whole directory and not even found any files like rootfs.ext2 or vmlinux, a major update may be needed. (sorry for the Inappropriate title before)