fix sccache issue on Windows CPU (#68870)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/68796
```
2021-11-24T10:12:40.7634007Z Compile requests 4312
2021-11-24T10:12:40.7634484Z Compile requests executed 4300
2021-11-24T10:12:40.7634823Z Cache hits 4227
2021-11-24T10:12:40.7635122Z Cache hits (C/C++) 4227
2021-11-24T10:12:40.7636139Z Cache misses 62
2021-11-24T10:12:40.7636930Z Cache misses (C/C++) 62
2021-11-24T10:12:40.7637333Z Cache timeouts 0
2021-11-24T10:12:40.7637839Z Cache read errors 0
2021-11-24T10:12:40.7638161Z Forced recaches 0
2021-11-24T10:12:40.7638489Z Cache write errors 0
2021-11-24T10:12:40.7638828Z Compilation failures 1
2021-11-24T10:12:40.7639180Z Cache errors 10
2021-11-24T10:12:40.7639490Z Cache errors (C/C++) 10
2021-11-24T10:12:40.7639856Z Non-cacheable compilations 0
2021-11-24T10:12:40.7640244Z Non-cacheable calls 0
2021-11-24T10:12:40.7640601Z Non-compilation calls 12
2021-11-24T10:12:40.7640987Z Unsupported compiler calls 0
2021-11-24T10:12:40.7641426Z Average cache write 0.104 s
2021-11-24T10:12:40.7641763Z Average cache read miss 6.000 s
2021-11-24T10:12:40.7642110Z Average cache read hit 0.046 s
2021-11-24T10:12:40.7642485Z Failed distributed compilations 0
```
https://github.com/pytorch/pytorch/runs/4310176911?check_suite_focus=true
cc seemethere malfet pytorch/pytorch-dev-infra
Pull Request resolved: https://github.com/pytorch/pytorch/pull/68870
Reviewed By: ejguan
Differential Revision: D32646289
Pulled By: janeyx99
fbshipit-source-id: bf04446439e55a4ccaf9ce7c77812752ca717a7c