Foundation: Provide a Hashable.hashValue witness for _BridgedStoredNSError conformers
Foundation: Provide a Hashable.hashValue witness for _BridgedStoredNSError conformers

Previously we would synthesize this in Sema, but this no longer
works when conformance checking is triggered by SILGen.

apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation