engine: simplifiy equivalent code (#38691)

The two branches built the same string.

bijoe/engine.py

@@ -462,10 +462,7 @@ class EngineCube(object):
             join_tree.setdefault(master_table, {}).setdefault(join.kind, {})[join.name] = join
 
         def build_table_expression_helper(join_tree, table_name, alias=None, top=True, other_conditions=None):
-            if table_name.strip().startswith('('):
-                sql = table_name
-            else:
-                sql = '%s' % table_name
+            sql = table_name
             if alias:
                 sql += ' AS %s' % quote(alias)
             add_paren = False