[clang] [clang-scan-deps] Expand response files before the argument adjuster (PR #89950)

[Alexandre Ganea via cfe-commits]

aganea wrote:

@jansvoboda11 PTAL.

I've added handling of `/Fo` in the driver, and that solves my case without the .rsp expansion in `ClangScanDeps.cpp`. However if we pass `/E` to command-lines in the CDB, that change alone doesn't work anymore. This is because `Driver::GetNamedOutputPath()` returns "-" here: https://github.com/llvm/llvm-project/blob/main/clang/lib/Driver/Driver.cpp#L5871

@sylvain-audi worked around that by adding `-o file.o` from the adjuster callback, which happens to bypass that condition a bit earlier, here: https://github.com/llvm/llvm-project/blob/main/clang/lib/Driver/Driver.cpp#L5853

I'm not sure that's right, ideally we should pass `-MT` from the adjuster but somehow that doesn't work. This would probably need to be revisited later.

https://github.com/llvm/llvm-project/pull/89950