parse.y: Use nd_loc of head and tail

* parse.y (block_append_gen): Use nd_loc of
  head(tail) when create NEW_BLOCK of head(tail).

  e.g. The locations of the NODE_BLOCK is fixed:

  ```
  BEGIN {
    :a
  }

  BEGIN {
    :b
  }
  ```

  * Before

  ```
  NODE_BLOCK (line: 5, code_range: (5,0)-(7,1))
  ```

  * After

  ```
  NODE_BLOCK (line: 1, code_range: (1,0)-(7,1))
  ```

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61686 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

parse.y

@@ -8852,7 +8852,7 @@ block_append_gen(struct parser_params *parser, NODE *head, NODE *tail, const YYL
 	parser_warning(h, "unused literal ignored");
 	return tail;
       default:
-	h = end = NEW_BLOCK(head, location);
+	h = end = NEW_BLOCK(head, &head->nd_loc);
 	end->nd_end = end;
 	head = end;
 	break;
@@ -8878,7 +8878,7 @@ block_append_gen(struct parser_params *parser, NODE *head, NODE *tail, const YYL
     }
 
     if (nd_type(tail) != NODE_BLOCK) {
-	tail = NEW_BLOCK(tail, location);
+	tail = NEW_BLOCK(tail, &tail->nd_loc);
 	tail->nd_end = tail;
     }
     end->nd_next = tail;