Make BytecodeGen work with Java 9.

The name of the sun.reflect package has changed to jdk.internal.reflect
in Java 9.  This was stopping the open-source testGuiceWorksInOSGiContainer test
from passing.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=183320310

core/src/com/google/inject/internal/BytecodeGen.java

@@ -395,7 +395,7 @@ private static class BridgeClassLoader extends ClassLoader {
     @Override
     protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
 
-      if (name.startsWith("sun.reflect")) {
+      if (name.startsWith("sun.reflect") || name.startsWith("jdk.internal.reflect")) {
         // these reflection classes must be loaded from bootstrap class loader
         return SystemBridgeHolder.SYSTEM_BRIDGE.classicLoadClass(name, resolve);
       }