Add soft-float ColdFire to build-many-glibcs.py.

Add soft-float ColdFire to build-many-glibcs.py.

Since it turns out soft-float ColdFire has a different glibc ABI to
hard-float ColdFire, as well as various differences in which glibc
code gets built, this patch adds such a configuration to
build-many-glibcs.py to (hopefully) complete the set of ABIs being
tested.  (Note that the build for soft-float ColdFire is currently
broken even with GCC mainline - I have a glibc patch to fix this, but
it needs before-and-after build-many-glibcs.py comparison of stripped
binaries for all configurations before being committed.)

	* scripts/build-many-glibcs.py (Context.add_all_configs): Add
	soft-float ColdFire configuration.