Revert "[clang][Dependency Scanning] Fix the In-Memory Buffer Used for By-Name Scanning" (#185150)
Reverts llvm/llvm-project#183396 due to buildbot breakage (e.g.,
https://lab.llvm.org/buildbot/#/builders/55/builds/25102; reported
earlier in
https://github.com/llvm/llvm-project/pull/183396#issuecomment-4015167408)
(Specifically, ASan is allergic to:
```
static const std::string
FakeInput(" ",
clang::tooling::CompilerInstanceWithContext::MaxNumOfQueries);
```)