Remove cancel and make crash exit with code 253.

sdk/lib/_internal/compiler/implementation/js_backend/constant_emitter.dart

Index: sdk/lib/_internal/compiler/implementation/js_backend/constant_emitter.dart
diff --git a/sdk/lib/_internal/compiler/implementation/js_backend/constant_emitter.dart b/sdk/lib/_internal/compiler/implementation/js_backend/constant_emitter.dart
index f19fc1bb53b76693964c54206f09ac9edb4c2a48..6d7eb6b039a8ab2c06435f03577e1b88020faff0 100644
--- a/sdk/lib/_internal/compiler/implementation/js_backend/constant_emitter.dart
+++ b/sdk/lib/_internal/compiler/implementation/js_backend/constant_emitter.dart
@@ -179,8 +179,8 @@ class ConstantInitializerEmitter implements ConstantVisitor<jsAst.Expression> {
   }
 
   jsAst.Expression visitFunction(FunctionConstant constant) {
-    compiler.internalError(
-        "The function constant does not need specific JS code");
+    compiler.internalError(NO_LOCATION_SPANNABLE,
+        "The function constant does not need specific JS code.");
     return null;
   }
 
@@ -274,7 +274,7 @@ class ConstantInitializerEmitter implements ConstantVisitor<jsAst.Expression> {
           } else if (field.name == MapConstant.JS_DATA_NAME) {
             arguments.add(jsGeneralMap());
           } else {
-            compiler.internalError(
+            compiler.internalError(field,
                 "Compiler has unexpected field ${field.name} for "
                 "${className}.");
           }
@@ -287,7 +287,7 @@ class ConstantInitializerEmitter implements ConstantVisitor<jsAst.Expression> {
          emittedArgumentCount != 4) ||
         (className == MapConstant.DART_GENERAL_CLASS &&
          emittedArgumentCount != 1)) {
-      compiler.internalError(
+      compiler.internalError(classElement,
           "Compiler and ${className} disagree on number of fields.");
     }