relax test_dont_hold_on_to_large_messages (#2264)
relax test_dont_hold_on_to_large_messages (#2264)

I suspect that this mail fail sometimes because we refresh the reference to x
every 50ms, which may be too short for GC?  Just a guess.
dask/distributed,dask/distributed,dask/distributed,dask/distributed,blaze/distributed,mrocklin/distributed,mrocklin/distributed,blaze/distributed,mrocklin/distributed