unique_ptrify RuntimeDyld::Dyld

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217180 91177308-0d34-0410-b5e6-96231b3b80d8
Fix use-after-move introduced in r217065 and caught in post-commit review by Alexey.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217181 91177308-0d34-0410-b5e6-96231b3b80d8