[DAGCombiner] don't hoist logic op if operands have other uses, part 2

The PPC test with 2 extra uses seems clearly better by avoiding this transform. 
With 1 extra use, we also prevent an extra register move (although that might
be an RA problem). The general rule should be to only make a change here if
it is always profitable. The x86 diffs are all neutral.

llvm-svn: 348518