[JIT] Modify is_mutable in FunctionSchema and SchemaInfo to have SchemaArgument parameter instead of index (#81784)

- Modify the is_mutable(size_t index) overload to become is_mutable(const SchemaArgument& argument) due to cases where one might want to check the mutability of either input or output arguments.
- Refactored all calls to the function to use this new overload
- Tested through is_mutable() tests in test_schema_info.cpp
Pull Request resolved: https://github.com/pytorch/pytorch/pull/81784
Approved by: https://github.com/davidberard98

torch/csrc/jit/python/init.cpp

@@ -1676,7 +1676,9 @@ void initJITBindings(PyObject* module) {
       .def("is_mutable", [](SchemaInfo& self) { return self.is_mutable(); })
       .def(
           "is_mutable",
-          [](SchemaInfo& self, size_t index) { return self.is_mutable(index); })
+          [](SchemaInfo& self, const SchemaArgument& argument) {
+            return self.is_mutable(argument);
+          })
       .def(
           "is_mutable",
           [](SchemaInfo& self, const std::string& name) {