* compile.c (iseq_peephole_optimize): remove unreachable code
chunk after jump/leave.
* parse.y: move dead code elimination of logical operation to
compile.c. not to warn logical operation of literal constants.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52711 b2dd03c8-39d4-4d8f-98ff-823fe69b080e