[emacs mode] Factor tern-ac-js-major-modes into a defvar
[emacs mode] Factor tern-ac-js-major-modes into a defvar

Issue #546

albertinad/tern,emacsmirror/tern,cdosborn/tern,anandthakker/tern,ternjs/tern,emallson/tern,MarcelGerber/tern,dorellang/tern,emacsmirror/tern,jgiles/tern,fileability/tern,emallson/tern,adrianton3/tern,messfairy/tern,marijnh/tern,othree/tern,messfairy/tern,cdosborn/tern,rustemferreira/tern,fileability/tern,adrianton3/tern,neoclide/tern,ternjs/tern,fileability/tern,emallson/tern,marijnh/tern,jgiles/tern,neoclide/tern,MarcelGerber/tern,mcanthony/tern,jgiles/tern,rustemferreira/tern,mcanthony/tern,marijnh/tern,emacsmirror/tern,adrianton3/tern,anandthakker/tern,cdosborn/tern,othree/tern,neoclide/tern,mcanthony/tern,albertinad/tern,dorellang/tern,othree/tern,messfairy/tern,talyian/tern,talyian/tern,MarcelGerber/tern,talyian/tern,dorellang/tern,anandthakker/tern,rustemferreira/tern,ternjs/tern,albertinad/tern