Remove some duplicates reported by genmatch

Remove some duplicates reported by genmatch

genmatch currently has a difficulty to decide whether a duplicate
structural match is really duplicate as uses of captures within
predicates or in C code can be order dependent.  For example
a reported duplicate results in

 {
   tree captures[4] ATTRIBUTE_UNUSED = { _p1, _p0, _q20, _q21 }
   if (gimple_simplify_112 (res_op, seq, valueize, type, captures))
     return true;
 }
 {
   tree captures[4] ATTRIBUTE_UNUSED = { _p1, _p0, _q21, _q20 };
   if (gimple_simplify_112 (res_op, seq, valueize, type, captures))
     return true;
 }

where the difference is only in _q20 and _q21 being swapped but
that resulting in a call to bitwise_inverted_equal_p (_p1, X)
with X once _q20 and once _q21.  That is, we treat bare
captures as equal for reporting duplicates.

Due to bitwise_inverted_equal_p there are meanwhile a _lot_ of
duplicates reported that are not actual duplicates.

The following removes some that are though, as the operands are
only passed to types_match.

	* match.pd (.SAT_ADD patterns using IFN_ADD_OVERFLOW): Remove :c that
	only causes duplicate patterns.