Revert "ruby: PoC/WIP/RFC key based filter of the top level hash"

This reverts commit b2ca5064a56f8fe01389c1eb9af7626cd8f37ccc and e7aec0659b7465a9eb840f46ec1c0a613e932f17
ruby: fix silence some warnings, fix a typo in decode:s_read_long_double