The SILGen testsuite consists of valid Swift code covering most language
features. We use these tests to verify that no unknown nodes are in the
file's libSyntax tree. That way we will (hopefully) catch any future
changes or additions to the language which are not implemented in
libSyntax.
Now that we properly track inherited conformances and don't re-emit the inherited conformance in every translation unit that asks for it, this is no longer necessary or correct. The necessary conformances for a file should be emitted while visiting the types in that file, and trying to recursively emit their dependencies introduces duplicate symbols. Fixes rdar://problem/21107266.
Swift SVN r29093
