Implement type argument access and reification of runtime types.

pkg/compiler/lib/src/tree_ir/tree_ir_tracer.dart

Index: pkg/compiler/lib/src/tree_ir/tree_ir_tracer.dart
diff --git a/pkg/compiler/lib/src/tree_ir/tree_ir_tracer.dart b/pkg/compiler/lib/src/tree_ir/tree_ir_tracer.dart
index 475bdaebcc83e98153b1237970018f9718d2ccbe..f7ecea41974f091b519fc6957375159c17a2087b 100644
--- a/pkg/compiler/lib/src/tree_ir/tree_ir_tracer.dart
+++ b/pkg/compiler/lib/src/tree_ir/tree_ir_tracer.dart
@@ -464,6 +464,16 @@ class SubexpressionVisitor extends ExpressionVisitor<String> {
     return 'CreateInstance $className($arguments)';
   }
 
+
+  @override
+  String visitReadTypeVariable(ReadTypeVariable node) {
+    return 'read ${node.variable.element} ${visitExpression(node.target)}';
+  }
+
+  @override
+  String visitReifyRuntimeType(ReifyRuntimeType node) {
+    return 'reify ${node.value}';
+  }
 }
 
 /**