Removed IllegalAccessException and UnsupportedOperationException.

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 efcb392b6ce5ccdfb44854c83c9ba2e17ecad2f3..dd153ab8905527ba3835b9a6ddf7db558708a8b9 100644
--- a/lib/compiler/implementation/elements/elements.dart
+++ b/lib/compiler/implementation/elements/elements.dart
@@ -231,11 +231,11 @@ class Element implements Spannable {
   Element get declaration => isPatch ? origin : this;
 
   Element get patch {
-    throw new UnsupportedOperationException('patch is not supported on $this');
+    throw new UnsupportedError('patch is not supported on $this');
   }
 
   Element get origin {
-    throw new UnsupportedOperationException('origin is not supported on $this');
+    throw new UnsupportedError('origin is not supported on $this');
   }
 
   // TODO(johnniwinther): This breaks for libraries (for which enclosing