<rdar://problem/13563697>
<rdar://problem/13563697>

The __NSArrayI synthetic children provider was running expressions to generate children, which is inefficient for large amounts of data
Reimplementing to use a faster algorithm

git-svn-id: 4c4cc70b1ef44ba2b7963015e681894188cea27e@178729 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/lldb,apple/swift-lldb,llvm-mirror/lldb,llvm-mirror/lldb,llvm-mirror/lldb,llvm-mirror/lldb,apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,apple/swift-lldb