Remove extra increment of plpgsql's statement counter for FOR loops.

This left gaps in the internal statement numbering, which is not
terribly harmful (else we'd have noticed sooner), but it's not
great either.

Oversight in bbd5c207; backpatch to v12 where that came in.

Pavel Stehule

Discussion: https://postgr.es/m/CAFj8pRDXyQaJmpotNTQVc-t-WxdWZC35V2PnmwOaV1-taidFWA@mail.gmail.com

src/pl/plpgsql/src/pl_gram.y

@@ -1341,7 +1341,6 @@ stmt_for		: opt_loop_label K_FOR for_control loop_body
 
 							new = (PLpgSQL_stmt_fori *) $3;
 							new->lineno   = plpgsql_location_to_lineno(@2);
-							new->stmtid	  = ++plpgsql_curr_compile->nstatements;
 							new->label	  = $1;
 							new->body	  = $4.stmts;
 							$$ = (PLpgSQL_stmt *) new;
@@ -1356,7 +1355,6 @@ stmt_for		: opt_loop_label K_FOR for_control loop_body
 							/* forq is the common supertype of all three */
 							new = (PLpgSQL_stmt_forq *) $3;
 							new->lineno   = plpgsql_location_to_lineno(@2);
-							new->stmtid	  = ++plpgsql_curr_compile->nstatements;
 							new->label	  = $1;
 							new->body	  = $4.stmts;
 							$$ = (PLpgSQL_stmt *) new;