Move all the builtin$ interceptors to a new interceptors library and shorten the names of them.

lib/compiler/implementation/elements/elements.dart

Index: lib/compiler/implementation/elements/elements.dart
diff --git a/lib/compiler/implementation/elements/elements.dart b/lib/compiler/implementation/elements/elements.dart
index e96db49c907d6d2635a90ce8f1b9dd1fc3a8306e..f15465d48814d010d3f8f606b49dd60346bf86a9 100644
--- a/lib/compiler/implementation/elements/elements.dart
+++ b/lib/compiler/implementation/elements/elements.dart
@@ -305,6 +305,12 @@ class LibraryElement extends CompilationUnitElement {
     return elements[elementName];
   }
 
+  Element findLocal(SourceString elementName) {

[floitsch, 2012/05/01 14:37:44]

add /**doc*/ for [findLocal] and [find].

+    Element result = elements[elementName];
+    if (result === null || result.getLibrary() != this) return null;
+    return result;
+  }
+
   void forEachExport(f(Element element)) {
     elements.forEach((SourceString _, Element e) {
       if (this === e.getLibrary()