Attempted fix for portability of uminusVsTimesPrec test

This test has been failing on prgenv-cray due to its reliance on
signed integer wraparound.  The intent of the test is interesting to
me (trying to rationalize relative precedence between unary minus and
multiplication), and a quick promotion of it from an int(32) test to
an int(64) test seems to work for prgenv-cray, so I'd like to try
running it that way to see if it makes it work everywhere.  If it
doesn't, we can decide to either skipif the test or retire it.
Merge pull request #781 from bradcray/attempted-fix-for-uminusVsTimesPrec

Attempted fix for portability of uminusVsTimesPrec test

This test has been failing on prgenv-cray due to its reliance on
signed integer wraparound.  The intent of the test is interesting to
me (trying to rationalize relative precedence between unary minus and
multiplication), and a quick promotion of it from an int(32) test to
an int(64) test seems to work for prgenv-cray, so I'd like to try
running it that way to see if it makes it work everywhere.  If it
doesn't, we can decide to either skipif the test or retire it.