[PATCH v2 15/17] fix some "exec" tests

[Tom Tromey]

Pedro> FYI, the "These tests have the correct file name compiled in."
Pedro> sentence confused me.  I'm not exactly sure what you meant
Pedro> by that.

I rewrote that paragraph as

    A few tests run an inferior that execs some other program.  The name
    of this exec'd program is compiled in.  These tests assume the current
    test suite directory layout, but fail in parallel mode.

Tom