compile.c: fix string Range optimization with FSL
The optimization in [Feature #13355] needs to be detected differently to work with "frozen_string_literal: true"
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62177 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
compile.c: fix string Range optimization with FSL
The optimization in [Feature #13355] needs to be detected
differently to work with "frozen_string_literal: true"
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62177 b2dd03c8-39d4-4d8f-98ff-823fe69b080e