Eliminate inappropriate use of FindProgramByName() from lli

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199835 91177308-0d34-0410-b5e6-96231b3b80d8
Handle an addrspacecast case in memcpyopt

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199836 91177308-0d34-0410-b5e6-96231b3b80d8