Added TestIntegerTypesExpr.py and TestFloatTypesExpr.py which exercise 'expr'

command on the various basic types, similar to TestIntegerTypes.py and
TestFloatTypes.py, which exercise 'frame variable' on the various basic types.

Right now, they don't employ the self.expect() facility to compare against the
golden output.  They just invoke the self.runCmd() method to run the 'expr'
command.  Decorated the two classes with @unittest2.skip decorators for the time
being.

llvm-svn: 114987