[ADT] Use try_emplace in SCCIterator.h (NFC)#164187

kazutakahirata merged 1 commit intollvm:mainllvm/llvm-project:mainfrom

kazutakahirata:cleanup_20251019_ADT_SCCIteratorkazutakahirata/llvm-project:cleanup_20251019_ADT_SCCIteratorCopy head branch name to clipboard