[Truffle] Basic new implementation of large hashes.
[Truffle] Fix default block in buckets hash.
[Truffle] Pull out some hash classes to the top level.
[Truffle] Tidy up RubyHash.
[Truffle] Make finding a bucket a node.
[Truffle] Some documentation of hash.
[Truffle] Fix a couple of hash bugs.
[Truffle] Make the bucket chain singly linked.
[Truffle] Rename buckets entries.
[Truffle] We don't need HashSearchResult as a DSL type at all.
[Truffle] Change hash guard terminology to PackedArray or Buckets
[Truffle] Make the packed array guard for hash, which is complicated by covariance, just the negation of the other two.
Merge pull request #2328 from jruby/truffle-hash

[Truffle] New implementation of non-small hashes