Make createObjectImage and createObjectImageFromFile static methods on the
relevant subclasses of RuntimeDyldImpl. This allows construction of
RuntimeDyldImpl instances to be deferred until after the target architecture is
known.
[C++11] Replacing EnumDecl iterators enumerator_begin() and enumerator_end() with iterator_range enumerators(). Updating all of the usages of the iterators with range-based for loops.