MethodInvocation was initiated with str sometimes, use Identifier

Author: joachimm

javalang/parser.py

@@ -2268,7 +2268,8 @@ def parse_selector(self):
 
             token = self.tokens.look()
             if isinstance(token, Identifier):
-                identifier = self.tokens.next().value
+                identifier = tree.Identifier(value=self.tokens.next())
+                identifier._position = self.tokens.last().position
                 arguments = None
 
                 if self.would_accept('('):