ira: Skip some pseudos in move_unallocated_pseudos

ira: Skip some pseudos in move_unallocated_pseudos

This patch is to make move_unallocated_pseudos consistent
to what we have in function find_moveable_pseudos, where we
record the original pseudo into pseudo_replaced_reg only if
validate_change succeeds with newreg.  To ensure every
unallocated pseudo in move_unallocated_pseudos has expected
information, it's better to add a check and skip it if it's
unexpected.  This avoids possible ICEs in future.

gcc/ChangeLog:

	* ira.c (move_unallocated_pseudos): Check other_reg and skip if
	it isn't set.