[clang] [lld] [llvm] [LTO] enable `ObjCARCContractPass` only on optimized build (PR #101114)

[Peter Rong via cfe-commits]

DataCorrupted wrote:

Interesting, I didn't know DT is preserved during critical edge splitting. Just add the line to preserve DT. Many DT Construction is removed from the tests.

https://github.com/llvm/llvm-project/pull/101114