[inputGraph] Associate Resolve state with appropriate nodes

This associates resolveState to FileNodes. The control node derive
their resolution state from the inputElements that are contained in
it.

This makes --start-group/--end-group to work with ELF linking.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@192269 91177308-0d34-0410-b5e6-96231b3b80d8