Fix --host-checked mode and add proper canBePrimitive method to HBoundedType.

tests/compiler/dart2js/type_combination_test.dart

Index: tests/compiler/dart2js/type_combination_test.dart
diff --git a/tests/compiler/dart2js/type_combination_test.dart b/tests/compiler/dart2js/type_combination_test.dart
index fb16be48c4f7ddba91908b7300e130d3f757446e..156bbcdbe4c6b491616bda0cb4999b4756837e1c 100644
--- a/tests/compiler/dart2js/type_combination_test.dart
+++ b/tests/compiler/dart2js/type_combination_test.dart
@@ -2033,7 +2033,7 @@ void testRegressions(MockCompiler compiler) {
 
 void main() {
   MockCompiler compiler = new MockCompiler();
-  compiler.interceptorsLibrary.forEachLocalMember((Element element) {
+  compiler.interceptorsLibrary.forEachLocalMember((element) {
     if (element.isClass()) {
       compiler.enqueuer.resolution.registerInstantiatedClass(element);
     }