Fix incorrect variable types for origin IDs in decode.c

These variables used XLogRecPtr instead of RepOriginId.

Author: Masahiko Sawada
Discussion: https://postgr.es/m/CAD21AoBm-vNyBSXGp4bmJGvhr=S-EGc5q1dtV70cFTcJvLhC=Q@mail.gmail.com
Backpatch-through: 14

Author: michaelpq

src/backend/replication/logical/decode.c

@@ -714,7 +714,7 @@ DecodePrepare(LogicalDecodingContext *ctx, XLogRecordBuffer *buf,
 	SnapBuild  *builder = ctx->snapshot_builder;
 	XLogRecPtr	origin_lsn = parsed->origin_lsn;
 	TimestampTz prepare_time = parsed->xact_time;
-	XLogRecPtr	origin_id = XLogRecGetOrigin(buf->record);
+	RepOriginId	origin_id = XLogRecGetOrigin(buf->record);
 	int			i;
 	TransactionId xid = parsed->twophase_xid;
 
@@ -790,7 +790,7 @@ DecodeAbort(LogicalDecodingContext *ctx, XLogRecordBuffer *buf,
 	int			i;
 	XLogRecPtr	origin_lsn = InvalidXLogRecPtr;
 	TimestampTz abort_time = parsed->xact_time;
-	XLogRecPtr	origin_id = XLogRecGetOrigin(buf->record);
+	RepOriginId	origin_id = XLogRecGetOrigin(buf->record);
 	bool		skip_xact;
 
 	if (parsed->xinfo & XACT_XINFO_HAS_ORIGIN)