[ADT] Simplify PointerBitMask in PointerIntPair.h (NFC)#158210

kazutakahirata merged 2 commits intollvm:mainllvm/llvm-project:mainfrom

kazutakahirata:cleanup_20250911_ADT_PointerIntPair_PointerBitMaskkazutakahirata/llvm-project:cleanup_20250911_ADT_PointerIntPair_PointerBitMaskCopy head branch name to clipboard