Implement the zygote debug options (late-enabling -Xcheck:jni and so on).

Change-Id: I03772e7fb95fce1a19dac13f6c5f870164a4d874
diff --git a/src/debugger.h b/src/debugger.h
index 388248b..2c2ade7 100644
--- a/src/debugger.h
+++ b/src/debugger.h
@@ -68,6 +68,8 @@
   static bool DebuggerStartup();
   static void DebuggerShutdown();
 
+  static void SetJdwpAllowed(bool allowed);
+
   // Return the DebugInvokeReq for the current thread.
   static DebugInvokeReq* GetInvokeReq();