Add a way to reset the thread pool of ThreadCoroutineSupport

* Needed for context pre-initialization to avoid serializing idle
  threads in the thread pool, which SVM does not support.

Remove unnecessary Class#hashCode() in PropertyImpl#hashCode()

* This is currently problematic on SVM, and is not needed anyway.

[GR-3686] Select explict variant when making overloaded method call.

Coroutines: update test for Graal as the package changed

[GR-3395] TruffleMap should return null value for a missing key.

[GR-3395] TruffleMap should return null value for a missing key.

[GR-2826] Allow invoking "bind" on arbitrary native pointers.

[GR-2826] Allow invoking "bind" on arbitrary native pointers.

Merge pull request oracle#341 in G/truffle from ~MARTIN.ENTLICHER_ORA…

…CLE.COM/truffle:TruffleTCK_uselessArgs to master

* commit '84ca1b9e1f836a3702a5bc6f27ef54d1478d9175':
  Remove unused null argument to TCK functions.

Merge pull request oracle#341 in G/truffle from ~MARTIN.ENTLICHER_ORA…

…CLE.COM/truffle:TruffleTCK_uselessArgs to master

* commit '84ca1b9e1f836a3702a5bc6f27ef54d1478d9175':
  Remove unused null argument to TCK functions.