[Truffle] Remove old benchmark reference data from ignore.
[Truffle] We don't want to pull in all of JRuby's stdlib at the moment.
[Truffle] Start our own stdlib path, delegating to JRuby's.
[Truffle] Import erb and cgi/util.
[Truffle] Bring in ERB specs from RubySL.
[Truffle] Range#begin.
[Truffle] Range#end.
[Truffle] Remove strange lowering on Range#include? - can't see why it's needed - will probably find out.
[Truffle] String#b.
[Truffle] Set up RubySL specs in truffle.mspec.
[Truffle] Add mvn -Ptruffle-specs-rubysl phase.
[Truffle] Add mvn -Ptruffle-specs-rubysl to Travis, but also to allowed failures for now.