[clang] [lld] [lldb] [llvm] [Option] Replace the OptionTables object with a function. NFC (PR #224805)

[Fangrui Song via cfe-commits]

MaskRay wrote:

> > Derive the prefix union from the prefix table in the constructor and drop the emitted OptionPrefixesUnion.
> 
> What's the motivation here? This doesn't look strictly required to be in the same patch, and I'd prefer that to be separate.

Extracted this simplification to a separate PR.

https://github.com/llvm/llvm-project/pull/224805