[PATCH] test-in-container: Install locales into the test container

[Florian Weimer]

* DJ Delorie:

> Perhaps we could at least add $(PARALLELMFLAGS) to the "make install" ?
> If it's not already propogated by some other means?  Or otherwise
> optimize the install process, to limit the overhead during testing?

$(MAKE) already implies $(PARALLELMFLAGS).

Thanks,
Florian