testsuite: fix jit.dg/test-error-impossible-must-tail-call.c [PR119783]

testsuite: fix jit.dg/test-error-impossible-must-tail-call.c [PR119783]

I added this test back in r7-934-g15c671a79ca66d, but it looks like
r15-2125-g81824596361cf4 changed the error message.

gcc/testsuite/ChangeLog:
	PR testsuite/119783
	jit.dg/test-error-impossible-must-tail-call.c
	* jit.dg/test-error-impossible-must-tail-call.c (verify_code):
	Check that we get a suitable-looking error message, but don't
	try to specify exactly what the message is.

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