[clang][deps] Move stripping of diagnostic serialization from `clang-scan-deps` to...

[clang][deps] Move stripping of diagnostic serialization from `clang-scan-deps` to `DependencyScanning` library

To prevent the creation of diagnostics file, `clang-scan-deps` strips the corresponding command-line argument. This behavior is useful even when using the C++ `DependencyScanner` library.

This patch transforms stripping of command-line in `clang-scan-deps` into stripping of `CompilerInvocation` in `DependencyScanning`.

AFAIK, the `clang-cl` driver doesn't even accept `--serialize-diagnostics`, so I've removed the test. (It would fail with an unknown command-line argument otherwise.)

Note: Since we're generating command-lines for modular dependencies from `CompilerInvocation`, the `--serialize-diagnostics` will be dropped. This was already happening in `clang-scan-deps` before this patch, but it will now happen also when using `DependencyScanning` library directly. This is resolved in D104036.

Reviewed By: dexonsmith, arphaman

Differential Revision: https://reviews.llvm.org/D104012