Drop itanium_demangler dependency

Index: angr/knowledge_plugins/functions/function.py
--- angr/knowledge_plugins/functions/function.py.orig
+++ angr/knowledge_plugins/functions/function.py
@@ -7,8 +7,6 @@ from collections import defaultdict
 from typing import Union, Optional, Iterable, Set, Generator
 from typing import Type # For some reasons the linter doesn't recognize the use in apply_definition but PyCharm needs it imported to correctly recognize it # pylint: disable=unused-import
 
-from itanium_demangler import parse
-
 from cle.backends.symbol import Symbol
 from archinfo.arch_arm import get_real_address_if_arm
 import claripy
@@ -1432,6 +1430,7 @@ class Function(Serializable):
 
     @property
     def demangled_name(self):
+        """
         if self.name[0:2] == "_Z":
             try:
                 ast = parse(self.name)
@@ -1439,6 +1438,7 @@ class Function(Serializable):
                 return self.name
             if ast:
                 return ast.__str__()
+        """
         return self.name
 
     def apply_definition(self, definition, calling_convention=None):
