[PR99663] Don't use unknown constraint for address constraint in process_address_1.

[PR99663] Don't use unknown constraint for address constraint in process_address_1.

s390x has insns using several alternatives with address constraints.  Even
if we don't know at this stage what alternative will be used, we still can say
that is an address constraint.  So don't use unknown constraint in this
case when there are multiple constraints or/and alternative.

gcc/ChangeLog:

	PR target/99663
	* lra-constraints.c (process_address_1): Don't use unknown
	constraint for address constraint.

gcc/testsuite/ChangeLog:

	PR target/99663
	* gcc.target/s390/pr99663.c: New.