[test] Remove spurious ABI change (?)

Author: lorentey

test/api-digester/Outputs/stability-stdlib-abi.swift.expected

@@ -323,7 +323,6 @@ Protocol _NSArrayCore has been removed
 Struct _CocoaArrayWrapper has type witness type for BidirectionalCollection.SubSequence changing from Slice<_CocoaArrayWrapper> to _SliceBuffer<AnyObject>
 Struct _CocoaArrayWrapper has type witness type for Collection.SubSequence changing from Slice<_CocoaArrayWrapper> to _SliceBuffer<AnyObject>
 Struct _CocoaArrayWrapper has type witness type for RandomAccessCollection.SubSequence changing from Slice<_CocoaArrayWrapper> to _SliceBuffer<AnyObject>
-Struct _CocoaArrayWrapper has type witness type for Sequence.SubSequence changing from Slice<_CocoaArrayWrapper> to _SliceBuffer<AnyObject>
 Var _ArrayBuffer._nonNative has declared type change from _NSArrayCore to _CocoaArrayWrapper
 Var _ArrayBuffer._storage has declared type change from _BridgeStorage<__ContiguousArrayStorageBase, _NSArrayCore> to _BridgeStorage<__ContiguousArrayStorageBase>
 Var _CocoaArrayWrapper.buffer has declared type change from _NSArrayCore to AnyObject