Remove dead code.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@205397 91177308-0d34-0410-b5e6-96231b3b80d8
Devirtualize Resolver.

No one inherits Resolver. Virtualizing the member functions was just
making it inefficient.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@205399 91177308-0d34-0410-b5e6-96231b3b80d8
Remove dead code.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@205401 91177308-0d34-0410-b5e6-96231b3b80d8
Remove unused variables.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@205402 91177308-0d34-0410-b5e6-96231b3b80d8