These are tests that fail in the next commit without this flag. This
does not add -verify-ignore-unrelated to all tests with -verify, only
the ones that would fail without it. This is NFC since this flag is
currently a no-op.
This used to be just a warning because it happened to work when clients
used only swiftmodules. Some projects have been using it as an
alternative to @_spiOnly imports. Now that we have an official feature
we can complete the diagnositc and error on implementation-only imports
types used in SPI.
