Normalize import paths for Sky modules

sky/framework/inspector/page-agent.sky

-<import src="/sky/framework/xmlhttprequest.sky" as="XMLHttpRequest" />
+<import src="../xmlhttprequest.sky" as="XMLHttpRequest" />
 <script>
 class Page {
   constructor(delegate) {
     this.delegate_ = delegate;
     Object.preventExtensions(this);
   }
 
   enable() {
   }
 
@@ skipping 87 matching lines @@
       if (element.shadowRoot) {
         roots.push(element.shadowRoot);
       }
     });
   }
   return map;
 }
 
 module.exports = Page;
 </script>