Enable full type-checks in checked mode.

sdk/lib/_internal/compiler/implementation/ssa/codegen.dart

Index: sdk/lib/_internal/compiler/implementation/ssa/codegen.dart
diff --git a/sdk/lib/_internal/compiler/implementation/ssa/codegen.dart b/sdk/lib/_internal/compiler/implementation/ssa/codegen.dart
index 42f055a7eda9f9a03265b893735585b4d292ce2d..9897ad0e6bf871afabe08909a21af8ab457f5234 100644
--- a/sdk/lib/_internal/compiler/implementation/ssa/codegen.dart
+++ b/sdk/lib/_internal/compiler/implementation/ssa/codegen.dart
@@ -2305,7 +2305,8 @@ abstract class SsaCodeGenerator implements HVisitor, HBlockInformationVisitor {
     world.registerIsCheck(type, work.resolutionTree);
     HInstruction input = node.expression;
 
-    if (node.isVariableCheck || node.isCompoundCheck) {
+    if (node.isVariableCheck || node.isCompoundCheck ||
+        node.isCheckedModeTest) {
       use(node.checkCall);
     } else {
       assert(node.isRawCheck);
@@ -2367,7 +2368,7 @@ abstract class SsaCodeGenerator implements HVisitor, HBlockInformationVisitor {
         attachLocationToLast(node);
       }
     }
-    if (node.nullOk) {
+    if (!node.isCheckedModeTest && node.nullOk) {
       checkNull(input);
       push(new js.Binary('||', pop(), pop()), node);
     }