swift234

XCTAssert(true, "Pass") crashes in Swift

Instead of trying to bridge NSDictionary to [String:String], XCTest needs to
just request the objects from the NSDictionary as String.

Also, move the unwrapping of the optional from the might-throw block such that
it only happens when the block hasn't thrown. Unwrapping the optional if the
block has thrown would crash, because the optional would still be unset.

Addresses <rdar://problem/17952584>.

Swift SVN r21119