Stop test-in-container trying to run other-OS binaries

[DJ Delorie]

Joseph Myers <joseph@codesourcery.com> writes:
> In this case, the x86 architecture means the binary executes, but
> dumps core rather than actually working.

Because cross-compiled, I assume?

> Anything involving running the newly built glibc should only be done
> ifeq ($(run-built-tests),yes).  This patch conditions the relevant
> part of the testroot setup accordingly.

Can $(run-built-tests) ever change from run to run, for the same build?
I mean, it's not dependent on some external environment variables or
ssh-to-target settings?

If it can't change, we don't (shouldn't?) need the testroot *at all*,
because test-container will never run either.