!2067 Fix cast check_elim

Merge pull request !2067 from BowenK/op_elim

mindspore/ops/operations/array_ops.py

@@ -186,11 +186,13 @@ class Cast(PrimitiveWithInfer):
         self.init_prim_io_names(inputs=['x', 'dst_type'], outputs=['output'])
 
     def check_elim(self, x, dtype):
-        if isinstance(x, Tensor):
-            if x.dtype == dtype:
+        if  isinstance(x, (Tensor, numbers.Number)):
+            if isinstance(x, Tensor) and x.dtype == dtype:
                 return (True, x)
+            if isinstance(x, numbers.Number):
+                return (True, Tensor(x, dtype=dtype))
             return (False, None)
-        raise ValueError("Expecting (Tensor, dtype), got : {}".format(inputs))
+        raise ValueError(f"Expecting (Tensor, dtype), got : ({x}, {dtype})")
 
     def __infer__(self, x, t):
         src_type = x['dtype']