[export] Change runtime asserts to using assert_scalar (#119608)
By changing runtime symbolic asserts to using assert_scalar, the asserts can call into `expect_true` and modify the shape env so that we can run through the traced graph module with fake tensors. With assert_async, the asserts only get hit during runtime, but that means if we run the graph module with fake tensors, the asserts will not affect the shape env, so later data dependent calls to the fake tensors may result in GuardOnDataDependentSymNode errors.
https://github.com/pytorch/pytorch/issues/119587
Pull Request resolved: https://github.com/pytorch/pytorch/pull/119608
Approved by: https://github.com/ezyang
