When one configures their toolchain to use a define (`-D`) in either
`SWIFT_FRONTEND_TEST_OPTIONS` or `SWIFT_DRIVER_TEST_OPTIONS`, the
DIModule generated by this test might have other elements like
`configMacros` in between `name:` and `includePath:`.
To account for this possibility, break the check in two, using
`CHECK-SAME` for the second part.
✔ More informative error messages in case of crashes.
✔ Handling and documenting different cases.
✔ Test cases for different cases.
✔ Make SDKDependencies.swift pass again.
When a Swift module built with debug info imports a library without
debug info from a textual interface, the textual interface is
necessary to reconstruct types defined in the library's interface. By
recording the Swift interface files in DWARF dsymutil can collect them
and LLDB can find them.
rdar://problem/49751363
