Find-all-refs for untyped modules

TypeScript Version: nightly (2.2.0-dev.20170210)

Code: tests/cases/fourslash/ambientShorthandFindAllRefs.ts

Expected behavior:

We can find all references of a symbol imported from an untyped module.

Actual behavior:

We don't have symbols attached to the module, just local symbols. So there's no good way to find references. Before #14001 we could do it by matching the name, we can do better.

After talking with @mhegazy, this isn't worth the effort since we can't reliably provide services for untyped modules.