Shrink instead of reshape to unregister symbolic (#12241)

* Slice to unbind symbolic

* use vmax for now

* assert shape in reshape is valid

* update test_symbolic_ops to use shrink instead of reshape

* remove infer_with_bound_values for npw

* symbolic output doesnt have symbolic strides

* symbolic jit tests use shrink to unregister symbolic

* update test

* update more tests

* wrap vmax in int()

* only create a new st if the store is not an assigne

* unwrap st

* comments

test/unit/test_symbolic_shapetracker.py

@@ -197,7 +197,7 @@ class TestSymbolicPad(unittest.TestCase):
   def test_pad(self):
     v = Variable("v", 1, 100).bind(5)
     t = Tensor.ones(100)[:v].pad(((4, 0),))
-    t = t.reshape(9)
+    t = t[:9]
     assert t.tolist() == [0,0,0,0,1,1,1,1,1]