Arm backend: Fix mypy warnings in test_insert_int32_casts_after_... (#15630)

Fix mypy warnings in
test_insert_int32_casts_after_int64_placeholders_pass.py about using
Tensor instead of LongTensor.

Signed-off-by: per.held@arm.com

Author: perheld

backends/arm/test/passes/test_insert_int32_casts_after_int64_placeholders_pass.py

@@ -53,13 +53,13 @@ def test_int64_model_tosa_FP():
 class UpcastToInt64ForIndexCopyInplaceModel(torch.nn.Module):
     aten_op = "torch.ops.aten.index_copy_.default"
 
-    def forward(self, x: torch.Tensor, index: torch.LongTensor, y: torch.tensor):
+    def forward(self, x: torch.Tensor, index: torch.LongTensor, y: torch.Tensor):
         return x.index_copy_(0, index, y)
 
     def get_inputs(self) -> input_t3:
         return (
             torch.zeros(5, 3),
-            torch.tensor([0, 4, 2]),
+            torch.LongTensor([0, 4, 2]),
             torch.tensor([[1, 2, 3], [4, 5, 6], [7, 8, 9]], dtype=torch.float),
         )
 
@@ -85,13 +85,13 @@ def test_upcast_to_int64_for_index_copy_inplace_tosa_INT():
 class UpcastToInt64ForIndexCopyModel(torch.nn.Module):
     aten_op = "torch.ops.aten.index_copy.default"
 
-    def forward(self, x: torch.Tensor, index: torch.LongTensor, y: torch.tensor):
+    def forward(self, x: torch.Tensor, index: torch.LongTensor, y: torch.Tensor):
         return x.index_copy(0, index, y)
 
     def get_inputs(self) -> input_t3:
         return (
             torch.zeros(5, 3),
-            torch.tensor([0, 4, 2]),
+            torch.LongTensor([0, 4, 2]),
             torch.tensor([[1, 2, 3], [4, 5, 6], [7, 8, 9]], dtype=torch.float),
         )