[ClangImporter] Use existential Any instead of the constraint when importing

dependent member types.

Author: hborla

lib/ClangImporter/ImportType.cpp

@@ -229,7 +229,7 @@ namespace {
 
     // TODO: Add support for dependent types (SR-13809).
 #define DEPENDENT_TYPE(Class, Base)                                            \
-  ImportResult Visit##Class##Type(const clang::Class##Type *) { return Impl.SwiftContext.TheAnyType; }
+  ImportResult Visit##Class##Type(const clang::Class##Type *) { return Impl.SwiftContext.getAnyExistentialType(); }
 #define TYPE(Class, Base)
 #include "clang/AST/TypeNodes.inc"