Add a .skipif for new future that PGI doesn't handle cleanly

The PGI compiler doesn't like -0.0i and turns it into positive 0.0i.  Skip
this test if CHPL_TARGET_COMPILER contains pgi.
Merge pull request #151 from daviditen/newFutures

Add a .skipif for new future that PGI doesn't handle cleanly

The PGI compiler doesn't like -0.0i and turns it into positive 0.0i. Skip
this test if CHPL_TARGET_COMPILER contains pgi.