[compiler-rt] [scudo] Refactor allocator config to support optional flags (PR #81805)

[via llvm-commits]

ChiaHungDuan wrote:

> Is it worth removing the MaySupportMemoryTagging = false for the FuchsiaConfig?

My preference is to let each project manage their configuration (like removing unused flags). In addition, the configs in upstream are supposed to be deprecated later, we can review and clean them up at that moment

https://github.com/llvm/llvm-project/pull/81805