New testcases.


gcc/testsuite/ChangeLog:

2017-05-18  Robin Dapp  <rdapp@linux.vnet.ibm.com>

	* gcc.dg/wrapped-binop-simplify-signed-1.c: New test.
	* gcc.dg/wrapped-binop-simplify-unsigned-1.c: New test.
	* gcc.dg/wrapped-binop-simplify-unsigned-2.c: New test.