[Pytorch] aten::stack (#103344)
Summary:
Stack: https://pytorch.org/docs/stable/generated/torch.stack.html
This diff uses `at::unsqueeze` and `at::cat` to implement `at::stack` for all dims
Re-organize the tests to 1d, 2d, 3d tensors.
Test Plan:
```
lfq@lfq-mbp fbsource % buck run --target-platforms ovr_config//platform/macos:arm64-fbsource //xplat/caffe2:pt_vulkan_api_test_binAppleMac\#macosx-arm64 -c pt.vulkan_full_precision=1 -- --gtest_filter="*stack*"
Restarting Buck daemon because Buck version has changed...
Buck daemon started.
Parsing buck files: finished in 9.1 sec
Creating action graph: finished in 0.7 sec
Downloaded 54/3888 artifacts, 27.68 Mbytes, 97.3% cache miss (for updated rules)
Building: finished in 07:36.5 min (100%) 2487/2487 jobs, 2487/2487 updated
Total time: 07:46.3 min
BUILD SUCCEEDED
Running main() from xplat/third-party/gmock/googletest-1.12.1/googletest/src/gtest_main.cc
Note: Google Test filter = *stack*
[==========] Running 4 tests from 1 test suite.
[----------] Global test environment set-up.
[----------] 4 tests from VulkanAPITest
[ RUN ] VulkanAPITest.stack_invalid_inputs
[ OK ] VulkanAPITest.stack_invalid_inputs (499 ms)
[ RUN ] VulkanAPITest.stack_1d
[ OK ] VulkanAPITest.stack_1d (6 ms)
[ RUN ] VulkanAPITest.stack_2d
[ OK ] VulkanAPITest.stack_2d (12 ms)
[ RUN ] VulkanAPITest.stack_3d
[ OK ] VulkanAPITest.stack_3d (130 ms)
[----------] 4 tests from VulkanAPITest (649 ms total)
[----------] Global test environment tear-down
[==========] 4 tests from 1 test suite ran. (649 ms total)
[ PASSED ] 4 tests.
lfq@lfq-mbp fbsource %
```
Reviewed By: yipjustin
Differential Revision: D46178424
Pull Request resolved: https://github.com/pytorch/pytorch/pull/103344
Approved by: https://github.com/SS-JIA
