SystemLibraryManager refactor - to separate package and sdk library functionality

compiler/javatests/com/google/dart/compiler/SystemLibraryManagerTest.java

Index: compiler/javatests/com/google/dart/compiler/SystemLibraryManagerTest.java
===================================================================
--- compiler/javatests/com/google/dart/compiler/SystemLibraryManagerTest.java	(revision 10981)
+++ compiler/javatests/com/google/dart/compiler/SystemLibraryManagerTest.java	(working copy)
@@ -22,6 +22,7 @@
   }
 
   SystemLibraryManager systemLibraryManager = new SystemLibraryManager();
+ 
 
   public void testExpand1() throws Exception {
     URI shortUri = new URI("dart:core");
@@ -87,6 +88,7 @@
   }
   
   public void testPackageExpand1() throws Exception {
+    systemLibraryManager.setPackageRoots(null);
     URI shortUri = new URI("package:test.dart");
     URI fullUri = systemLibraryManager.expandRelativeDartUri(shortUri);
     assertNotNull(fullUri);