[clang] [clang][Dependency Scanning] Fix the In-Memory Buffer Used for By-Name Scanning (PR #183396)

[Thurston Dang via cfe-commits]

thurstond wrote:

ASan doesn't like

```
static const std::string
    FakeInput(" ",
              clang::tooling::CompilerInstanceWithContext::MaxNumOfQueries);
```
in clang/lib/Tooling/DependencyScanningTool.cpp

(minimized snippet: https://godbolt.org/z/1daYPr7ob)

https://github.com/llvm/llvm-project/pull/183396