swift234

Runtime: Fix memory leak when swift_dynamicCast does a copy_on_success bridging cast.

In the course of preparing the bridging object to be bridged to a Swift value, we forwarded the cast flags to _dynamicCastUnknownClass unaltered, which caused a leak for copy-on-success casts since it introduced an extra retain. Fix this by simplifying _dynamicCastUnknownClass to have no retain/release behavior of its own. Fixes rdar://problem/22587077.

Swift SVN r31841