swift234

Clang importer: Preserve the delayed protocol conformance behavior in playground mode.

The fix for rdar://problem/19924834 introduced a 10% performance hit when importing Foundation. Playgrounds are performance-sensitive, and ought to be able to keep working without the fix, because they're never multi-file and it's not yet possible to dynamically access an Equatable or RawRepresentable conformance using 'is' or 'as'. Preserve the old behavior in playground mode, until we have time to recover the performance hit in a more principled way (covered by rdar://problem/20047340).

Swift SVN r25772