DTD TILE_OF issue combining with DONT_TRACK

[abouteiller]

Original report by Yu Pei (Bitbucket: [Yu Pei](https://bitbucket.org/Yu Pei), ).

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When use DTD TILE_OF to access data but at the same time also use DONT_TRACK flag (doing my own task dependency tracking with Future), I will sporadically get segfault due to blowing up of hash table.