[clang] Reland "[clang][ssaf][NFC] Move SSAF flags from FrontendOptions to a dedicated SSAFOptions" (PR #204798)

[Balázs Benics via cfe-commits]

steakhal wrote:

Some context for you @ziqingluo-90:
- `SSAFOptions.h` conceptually lived within the `clangScalableStaticAnalysisFrameworkFrontend` library - (look at the file path)
- `CompilerInvocation.cpp` lives within the `clangFrontend` library.
- `clangScalableStaticAnalysisFrameworkFrontend` links against `clangFrontend`.

This means that `clangFrontend` should not include `SSAFOptions.h` (from `clangScalableStaticAnalysisFrameworkFrontend`) because that would introduce a circular dependency:
`clangFrontend` -> `clangScalableStaticAnalysisFrameworkFrontend` -> `clangFrontend`

The solution was moving the header into `clangFrontend`. This way including it would NOT bring a dependency on `clangScalableStaticAnalysisFrameworkFrontend`, thus the circular dependency would be avoided.

https://github.com/llvm/llvm-project/pull/204798