[pytorch] fix hipify_python (#70619)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/70619
This Diff improves `hipify_python`, which is needed for AMD GPUs.
Change 1:
```
if (c == "," or ind == len(kernel_string) - 1) and closure == 0:
```
This is needed to deal with the following case (ex: https://github.com/pytorch/pytorch/blob/master/aten/src/ATen/test/cuda_vectorized_test.cu#L111)
```
kernel<<<val, func()>>>(...)
// In this case, kernel_string is "val, func()"
// so closure gets 0 when ind == len(kernel_string) - 1.
```
Change 2:
```
mask_comments()
```
This is needed to deal with a case where "<<<" is included in a comment or a string literal (ex: https://github.com/pytorch/pytorch/blob/master/torch/csrc/deploy/interpreter/builtin_registry.cpp#L71)
```
abc = "<<<XYZ>>>"
// Though this <<<XYZ>>> is irrelevant to CUDA kernels,
// the current script attempts to hipify this and fails.
```
Test Plan:
This patch fixes errors I encountered by running
```
python3 tools/amd_build/build_amd.py
```
I confirmed, with Linux `diff`, that this patch does not change HIP code that was generated successfully with the original script.
Reviewed By: hyuen
Differential Revision: D33407743
fbshipit-source-id: bec822e040a154be4cda1c294536792ca8d596ae
