[walker] Fix assumption that functions always have a block body
[walker] Fix assumption that functions always have a block body

btmills/acorn,TimothyGu/acorn,TimothyGu/acorn,TimothyGu/acorn,Rich-Harris/acorn,ternjs/acorn,btmills/acorn,ajaxorg/acorn,mathiasbynens/acorn,marijnh/acorn,ternjs/acorn,mysticatea/acorn,MarcelGerber/acorn,happibum/acorn,mysticatea/acorn,marijnh/acorn,happibum/acorn,happibum/acorn,btmills/acorn,ternjs/acorn,MarcelGerber/acorn,mathiasbynens/acorn,mysticatea/acorn,marijnh/acorn,ajaxorg/acorn,Rich-Harris/acorn,ajaxorg/acorn,Rich-Harris/acorn,mathiasbynens/acorn,MarcelGerber/acorn