This way, each kind of `ResolvedCursorInfo` can define its own set of properties and it’s obvious which properties are used for which kind. Also switch to getters and setters because that makes it easier to search for usages of properties by looking at the call hierarchy of the getter / setter.
IDE/Refactoring had dependencies to libswiftIndex, but libswiftIndex
also depends on libswiftIDE (SourceEntityWalker, etc.)
To break libswiftIndex <-> libswiftIDE dependency cycle, move
"refactoring" related files to a new library 'libswiftRefactoring'
rdar://101692282