Jar-globbing test does not update mtime on CloudBees

[headius]

For whatever reason, the "Dir globs (Dir.glob and Dir.[]) respects jar content filesystem changes" spec added by @ratnikov does not see mtime update when running on CloudBees. See an example failure here; the timestamps are clearly the same even with a 5s delay and successful "zip" archive modification.

This same spec passes on Travis, which is also Linux. @enebo theorized there might be some filesystem quirks at play on CloudBees, but I have not investigated that.

Will commit shortly to disable this spec until we can figure out what's up with the 'Bees.

[kares]

re-enabled and pended on CloudBees only ... 3950c09#diff-fddfbb9687989d3b1dad1c62387a81a7R99