swift

5bccbe56 - AST: Refactor `AvailabilityScope::getAvailabilityConditionVersionSourceRange()`.

AST: Refactor `AvailabilityScope::getAvailabilityConditionVersionSourceRange()`. Modify it to take an `AvailabilityDomain` and a `DeclContext` which will be necessary in order to compare `AvailabilitySpec`s in a later refactor.