[LTC] Make some LazyGraphExecutor private data structures protected (#90598)
Summary:
This pull request makes some LazyGraphExecutor private data structures protected such that XLAGraphExecutor can reuse them.
Here is the list:
1. DeviceLocker.
2. DeviceLockerArena.
3. DataCacheArena. In addition, it also introduces LazyGraphExecutor::ResetTrimCounter() such that XLAGraphExecutor can reuse the trim counter.
Test Plan:
CI.
P.S. This is to re-land #90457.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/90598
Approved by: https://github.com/JackCaoG
