V8 test-in-container patch

[DJ Delorie]

"Carlos O'Donell" <carlos@redhat.com> writes:
> OK for master with:

And having waited a few days for other comments, too...

Committed!  Thanks to all for reviews!

> - Review suggested text and accept or reject with rationale.

Accepted.  Thanks!

> - Fix error string typo in run_command_array.

Fixed.

> - Delete #if 0/#endif iconv/gconv code.

Deleted.

> - Successful build-many-glibcs run.

That took a while (because b-m-g takes a long time), and needed some
minor tweaks to handle the bootstrap step in build-many-glibcs.
Successful run with x86-linux and i686-hurd.  The Hurd maintainer will
need to provide suitable magic to containerize a test, later :-)