p9-extract-1.c: Make second argument of vec_extract a signed int.

p9-extract-1.c: Make second argument of vec_extract a signed int.

gcc/testsuite/ChangeLog:

2018-06-25  Carl Love  <cel@us.ibm.com>

	* gcc.target/powerpc/p9-extract-1.c: Make second argument of
 	vec_extract a signed int. Add vec_extract tests for bool char
	and bool int.
	* gcc.target/powerpc/p9-extract-4.c:  New test file for long long
	vec_extract tests.

From-SVN: r262023