[clang] [llvm] [Support][Modules] Removed prepareForGetLock and its usages. Ensured parent directory exists when creating lock file. (PR #189888)

[Jan Svoboda via cfe-commits]

https://github.com/jansvoboda11 commented:

Starts looking good except for the usage of `createUniqueFile()` that seems to be confusing the model and the resulting unique path.

https://github.com/llvm/llvm-project/pull/189888