Updated CI specs to RubySpec ee468c6b.
Fixed multi-byte symbol spec.
Fixed Proc#arity specs.
Updated CI tags for 1.8 mode.
Updated MSpec source to b6027016.
Updated CI tags for 1.9, 2.0.
Fixed Thread[.#]abort_on_exception specs.
Added missing file from rubygems 1.8.25 update.
Remove race from TCPSocket.new specs.

The SpecTCPServer does not echo when receiving QUIT so the read
would block, randomly, of course.
Some SocketSpecs::SpecTCPServer cleanups.
Restore Thread.abort_on_exception state.
More CI tags updates.
Updated CI specs to RubySpec 56c5528f.