Fix csp mode on platforms that don't support __proto__.

pkg/compiler/lib/src/js_emitter/full_emitter/setup_program_builder.dart

Index: pkg/compiler/lib/src/js_emitter/full_emitter/setup_program_builder.dart
diff --git a/pkg/compiler/lib/src/js_emitter/full_emitter/setup_program_builder.dart b/pkg/compiler/lib/src/js_emitter/full_emitter/setup_program_builder.dart
index feaee8eec8c1afe7c2dd32d97f17c70355604762..95c7dc4b0841cb494575e876132c25f12ad3148e 100644
--- a/pkg/compiler/lib/src/js_emitter/full_emitter/setup_program_builder.dart
+++ b/pkg/compiler/lib/src/js_emitter/full_emitter/setup_program_builder.dart
@@ -499,6 +499,7 @@ function $setupProgramName(programData, typesOffset) {
           chain = targetPrototype.#deferredAction;
         }
         return function foo() {
+          if (!supportsDirectProtoAccess) return;
           var prototype = this;
           // Find the actual prototype that this handler is installed on.
           while (!prototype.hasOwnProperty(#deferredActionString)) {