Remove the concept of staticly positioned absolutes.

sky/tests/layout/position-absolute-pixels-expected.sky

 <sky>
   <import src="../resources/run-after-display.sky"/>
 
-  <img src="http://storage.googleapis.com/mojo/sky-pngs/df9f2bee2247645ae83ed672858ee47fb239f70a" />
+  <img src="http://storage.googleapis.com/mojo/sky-pngs/0e49314437b063e76c28511c34a6c6da72c17956" />
 
   <script>
   import "dart:sky";
   import "dart:sky.internals" as internals;
 
   void main() {
     window.addEventListener("load", (_) {
       runAfterDisplay(() {
         internals.notifyTestComplete("");
       });
     });
   }
   </script>
 </sky>