read meta["val"] from arg for place holders instead of generating a fake tensor using fake_tensor_mode.from_real_tensor

Differential Revision: D65120377

Pull Request resolved: #6550

Author: laithsakka

exir/pass_base.py

@@ -453,7 +453,7 @@ def on_attr(self, attr: ProxyValue) -> None:
     def placeholder(self, name: str, arg: Argument, meta: NodeMetadata) -> ProxyValue:
         arg_proxy = self.tracer.create_proxy("placeholder", name, (), {})
         arg_proxy.node.meta = meta.data
-        self.tracer.set_metadata(arg_proxy.node, arg)
+        arg_proxy.node.meta["val"] = arg
         return ProxyValue(arg, arg_proxy)
 
     def call_operator(