[linker]: Also reference all type-references for LinkAction.Link and Save.
[linker]: Fix my previous commit.

We need to resolve all the TypeReferences before we update their scopes.
After setting the scope to null, calling Resolve() on a nested child would
crash.
Revert my last two commits; these would require a new cecil.

This reverts commits c29ac46c408aa2ae588548fa36a0aa9bf0b01014
and b31c9486e3dddb70cc877962a51e3bbe476c42eb.