* a64: Fix where hp1's was assumed to be an instruction and not actually checked

compiler/aarch64/aoptcpu.pas

@@ -532,6 +532,8 @@ Implementation
 
      else if GetNextInstruction(p, hp1) and
        (taicpu(p).ops=2) and
+       { Faster to get it out of the way than go through MatchInstruction }
+       (hp1.typ=ait_instruction) and
        (taicpu(hp1).ops=3) and
        MatchInstruction(hp1,[A_ADD,A_SUB],[taicpu(p).condition], [PF_None,PF_S]) and
        (getsubreg(taicpu(p).oper[0]^.reg)=R_SUBD) and