添加方法返回的字段为null

添加方法返回的字段为null,
以及modify与add嵌套使用时，也会报错

异常类型：app运行时异常

手机型号：三星S7

手机系统版本：Android 7.0

Robust版本：0.4.75

Gradle版本：4.1

系统：win

堆栈/日志：

java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object java.lang.reflect.Method.invoke(java.lang.Object, java.lang.Object[])' on a null object reference
at com.meituan.robust.utils.EnhancedRobustUtils.invokeReflectMethod(EnhancedRobustUtils.java:34)
at smartref.zxz.com.robusttest.patch.MainActivity$1Patch.onClick(MainActivity$1Patch.java:24)
at smartref.zxz.com.robusttest.patch.MainActivity$1PatchControl.accessDispatch(PatchTemplate.java)
at com.meituan.robust.PatchProxy.accessDispatch(PatchProxy.java:69)
at smartref.zxz.com.robusttest.MainActivity$1.onClick(MainActivity.java)
at android.view.View.performClick(View.java:6213)
at android.widget.TextView.performClick(TextView.java:11074)
at android.view.View$PerformClick.run(View.java:23645)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6646)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1468)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1358)

Start with the stack trace location in EnhancedRobustUtils.java, especially invokeReflectMethod, and inspect how the reported add operation and nested modify/add usage are handled. Reproduce the Android 7.0 case described for Robust 0.4.75, then verify that the returned field is not null and that the nested operations no longer raise the reported NullPointerException.