Implement latest spec changes regarding malformed types (see issue 14006):

runtime/lib/errors_patch.dart

Index: runtime/lib/errors_patch.dart
===================================================================
--- runtime/lib/errors_patch.dart	(revision 29604)
+++ runtime/lib/errors_patch.dart	(working copy)
@@ -37,7 +37,7 @@
 patch class TypeError extends AssertionError {
   TypeError._create(String url, int line, int column,
                     this._srcType, this._dstType, this._dstName,
-                    this._boundError)
+                    this._errorMsg)
       : super._create("is assignable", url, line, column);
 
   static _throwNew(int location,
@@ -48,12 +48,12 @@
       native "TypeError_throwNew";
 
   String toString() {
-    String str = (_boundError != null) ? _boundError : "";
+    String str = (_errorMsg != null) ? _errorMsg : "";
     if ((_dstName != null) && (_dstName.length > 0)) {
       str = "${str}type '$_srcType' is not a subtype of "
             "type '$_dstType' of '$_dstName'.";
     } else {
-      str = "${str}malbounded type used.";
+      str = "${str}malformed type used.";
     }
     return str;
   }
@@ -61,19 +61,19 @@
   final String _srcType;
   final String _dstType;
   final String _dstName;
-  final String _boundError;
+  final String _errorMsg;
 }
 
 patch class CastError extends Error {
   CastError._create(this._url, this._line, this._column,
                     this._srcType, this._dstType, this._dstName,
-                    this._boundError);
+                    this._errorMsg);
 
   // A CastError is allocated by TypeError._throwNew() when dst_name equals
   // Exceptions::kCastErrorDstName.
 
   String toString() {
-    String str = (_boundError != null) ? _boundError : "";
+    String str = (_errorMsg != null) ? _errorMsg : "";
     str = "${str}type '$_srcType' is not a subtype of "
           "type '$_dstType' in type cast.";
     return str;
@@ -86,7 +86,7 @@
   final String _srcType;
   final String _dstType;
   final String _dstName;
-  final String _boundError;
+  final String _errorMsg;
 }
 
 patch class FallThroughError {