Move SizeOfHeapNewCid next to xl_heap_new_cid struct.

They belong together, but the xl_heap_rewrite_mapping struct was wedged
in between.

src/include/access/heapam_xlog.h

@@ -349,6 +349,8 @@ typedef struct xl_heap_new_cid
 	xl_heaptid target;
 } xl_heap_new_cid;
 
+#define SizeOfHeapNewCid (offsetof(xl_heap_new_cid, target) + SizeOfHeapTid)
+
 /* logical rewrite xlog record header */
 typedef struct xl_heap_rewrite_mapping
 {
@@ -360,8 +362,6 @@ typedef struct xl_heap_rewrite_mapping
 	XLogRecPtr			start_lsn;	/* Insert LSN at begin of rewrite */
 } xl_heap_rewrite_mapping;
 
-#define SizeOfHeapNewCid (offsetof(xl_heap_new_cid, target) + SizeOfHeapTid)
-
 extern void HeapTupleHeaderAdvanceLatestRemovedXid(HeapTupleHeader tuple,
 									   TransactionId *latestRemovedXid);