This constructor was restored by deprecation patches from 10.0 in
jruby#9474 but the merge of that to 10.1 left it as a normal
non-delegated constructor. This patch makes the following changes:
* Make this constructor delegate, like the other deprecated
RubyHash constructors.
* Remove the protected constructor from RubyHashLinkedBuckets, so
that it lives only in RubyHash and we can be sure all callers
need delegation.
The constructor should move back into RubyHashLinkedBuckets as a
protected internal constructor once we can safely remove the
constructors from RubyHash (10.2 or later).
This does a final removal of all public RubyHash constructors, as discussed in #9456. This may or may not end up merging as-is, but is a reminded for 10.2 to revisit whether these constructors can finally be removed.