If someone has configured their build to add some vendor macro, for
example, the vendor macro will appear in `customConditions`, which will
make the test fail.
Modify the test slightly to check for `customConditions` containing
`"SOMETHING"`, instead of only being `["SOMETHING"]` and nothing else.
This should still allow the test to pass in Swift CI, but allows vendor
macros to work too.
Introduce the ability to form a `StaticBuildConfiguration` from
language options. Add a frontend option `-print-static-build-config`
to then print that static build configuration as JSON in a manner that
can be decoded into a `StaticBuildConfiguration`.
Most of the change here is in sinking the bridged ASTContext queries
of language options into a new BridgedLangOptions. The printing of the
static build configuration only has a LangOptions (not an ASTContext),
so this refactoring is required for printing.
