swift

18fcdaa7 - test: Skip attr_dynamic_member_lookup_default_args.swift in back deployment configs.

test: Skip attr_dynamic_member_lookup_default_args.swift in back deployment configs. Adjust a test from https://github.com/swiftlang/swift/pull/88480 so that it doesn't run on bot configs that don't support it. Also, use a real deployment target instead of `-disable-availability-checking`. Resolves rdar://181742095.