[WholeProgramDevirt] Add check for AvailableExternal and give up icall.branch.funnel#143468

tianleliu merged 5 commits intollvm:mainllvm/llvm-project:mainfrom

tianleliu:AvailExternCheck4WholeProgDevirttianleliu/llvm-project:AvailExternCheck4WholeProgDevirtCopy head branch name to clipboard