[browser defs] Add HTMLElement.matches() method.
[browser defs] Add HTMLElement.matches() method.

Closes #849

fileability/tern,othree/tern,MarcelGerber/tern,ternjs/tern,neoclide/tern,othree/tern,ternjs/tern,marijnh/tern,marijnh/tern,marijnh/tern,ternjs/tern,emacsmirror/tern,emacsmirror/tern,fileability/tern,neoclide/tern,MarcelGerber/tern,othree/tern,emacsmirror/tern,neoclide/tern,fileability/tern,MarcelGerber/tern