Revert 741978d727 and things that landed on top of it.

Revert 741978d727 and things that landed on top of it.

741978d727 made clang produce output that's 2x as large at least in
sanitizer builds. https://reviews.llvm.org/D83892#2470185 has a
standalone repro.

This reverts the following commits:

Revert "[clang][cli] Port CodeGenOpts simple string flags to new option parsing system"
This reverts commit 95d3cc67caac04668ef808f65c30ced60ed14f5d.

Revert "[clang][cli] Port LangOpts simple string based options to new option parsing system"
This reverts commit aec2991d083a9c5b92f94d84a7b3a7bbed405af8.

Revert "[clang][cli] Streamline MarshallingInfoFlag description"
This reverts commit 27b7d646886d499c70dec3481dfc3c82dfc43dd7.

Revert "[clang][cli] Port LangOpts option flags to new option parsing system"
This reverts commit 383778e2171b4993f555433745466e211e713548.

Revert "[clang][cli] Port CodeGen option flags to new option parsing system"
This reverts commit 741978d727a445fa279d5952a86ea634adb7dc52.