jit: fix test-vector-* failures

Fix failures seen on i686 due to relying on exact floating-point
equality when testing results of vector division.

gcc/testsuite/ChangeLog:
	* jit.dg/test-vector-rvalues.cc (check_div): Add specialization
	for v4f, to avoid relying on exact floating-point equality.
	* jit.dg/test-vector-types.cc (check_div): Likewise.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>