My last patch implementing output reloads in asm goto resulted in LRA 
crash in compiling kernel on s390x.  Jeff Law reported it recently.  The 
culprit was in incorrect emitting reload insns in last empty BB.  The 
emitted insns got null BB which is wrong. Actually in this case we do 
not need to emit such insns as they will removed as dead lately.

The following patch fixes the problem.