Rename RuntimeError to CyclicIntializationError, as per spec.

sdk/lib/_internal/compiler/implementation/lib/js_mirrors.dart

Index: sdk/lib/_internal/compiler/implementation/lib/js_mirrors.dart
diff --git a/sdk/lib/_internal/compiler/implementation/lib/js_mirrors.dart b/sdk/lib/_internal/compiler/implementation/lib/js_mirrors.dart
index aaf30d7d4b78978f1f6ffaf676206507b0a6776d..5b4f36a109a42e96bd7ca63087cfeee43b00a3d7 100644
--- a/sdk/lib/_internal/compiler/implementation/lib/js_mirrors.dart
+++ b/sdk/lib/_internal/compiler/implementation/lib/js_mirrors.dart
@@ -428,7 +428,7 @@ class JsVariableMirror implements VariableMirror {
     int length = descriptor.length;
     var code = fieldCode(descriptor.codeUnitAt(length - 1));
     if (code == 0) {
-      throw new RuntimeError('Bad field descriptor: $descriptor');
+      throw new ArgumentError('Bad field descriptor: $descriptor');
     }
     bool hasGetter = (code & 3) != 0;
     bool hasSetter = (code >> 2) != 0;
@@ -481,7 +481,7 @@ function(reflectee) {
 ''');
     String callName = JS('String|Null', '#(#)', extractCallName, reflectee);
     if (callName == null) {
-      throw new RuntimeError('Cannot find callName on "$reflectee"');
+      throw new ArgumentError('Cannot find callName on "$reflectee"');
     }
     int parameterCount = int.parse(callName.split(r'$')[1]);
     if (reflectee is BoundClosure) {