Implementing method #to_a for Hash instances.
[Truffle] Added rubyspecs to Hash#to_a.
[Truffle] - Removing rubyspec  added in the previously commit - These specs are automatically synced
with rubyspecs repository and should not be changed.
Method name must be in CamelCase format..
Merge pull request #1415 from lucasallan/implementing-method-to_a-for-hash

[Truffle] Implementing method #to_a for hash instances