[Static Runtime] Fix tensor_split sections overload (#88113)
Summary:
D40798763 broke this op. Unfortunately, it wasn't caught at land time due to the recent OSS Static Runtime test problems.
The problem is C++ overload resolution. After D40798763, the int that we were passing to `at::native::tensor_split` was getting implicitly converted to `IntArrayRef`. Fix this by converting the int to a `SymInt` and calling the correct overload.
Test Plan:
```
buck2 test caffe2/benchmarks/static_runtime:static_runtime_cpptest -- Tensor_Split --run-disabled
```
Differential Revision: D40862394
Pull Request resolved: https://github.com/pytorch/pytorch/pull/88113
Approved by: https://github.com/hlu1
