use sigjmp_buf for analyzer sigsetjmp tests

The sigsetjmp analyzer tests use jmp_buf in sigsetjmp and siglongjmp
calls.  Not every system that supports sigsetjmp uses the same data
structure for setjmp and sigsetjmp, which results in type mismatches.

This patch changes the tests to use sigjmp_buf, that is the
POSIX-specific type for use with sigsetjmp and siglongjmp.


for  gcc/testsuite/ChnageLog

	* gcc.dg/analyzer/sigsetjmp-5.c: Use sigjmp_buf.
	* gcc.dg/analyzer/sigsetjmp-6.c: Likewise.