DummyFramework.framework has two different properties to support two different kinds of test cases: to support ModuleInterface/build-alternative-interface-framework.swift, its macOS interfaces are broken, but to support ModuleInterface/arm64e-fallback.swift, it supports only arm64, not arm64e, on iOS. The arm64e test's behavior is about to change, which will complicate all of this. As a preliminary step, make the two tests use two different frameworks so they aren't so intertwined.
This temporarily keeps the arm64e test using the name "DummyFramework", but that will change.
