[Vulkan] Implement Stack operator (#81064)
Summary:
Implemented Stack operator for the Vulkan backend.
Special case implementation:
- Input tensor must be 2-dim, i.e. [H, W].
- dim must be 0, i.e the output tensor will be [C, H, W]
References
- PyTorch Docs > torch > [torch.stack](https://pytorch.org/docs/stable/generated/torch.stack.html)
Test Plan:
Added test cases to `/xplat/caffe2/aten/src/ATen/test/vulkan_api_test.cpp`
On Mac:
```
buck run //xplat/caffe2:pt_vulkan_api_test_binAppleMac
```
On Android:
```
buck build -c ndk.custom_libcxx=false -c pt.enable_qpl=0 //xplat/caffe2:pt_vulkan_api_test_binAndroid\#android-arm64 --show-output
adb push buck-out/gen/xplat/caffe2/pt_vulkan_api_test_binAndroid\#android-arm64 /data/local/tmp/vulkan_api_test
adb shell "/data/local/tmp/vulkan_api_test"
Differential Revision: D37699984
Pull Request resolved: https://github.com/pytorch/pytorch/pull/81064
Approved by: https://github.com/SS-JIA
