[alibaba/fastjson]序列化mock对象导致StackOverflowError错误

对一个mock对象执行 JSON.toJSON 会抛错

可能带来的影响是：如果做了try catch且在catch异常里面打日志（常见做法）等获取栈信息时，会引发StackOverflowError，该操作非常耗时，影响系统稳定性，甚至被利用做攻击

附：试了jackson和gson无此问题

• fastjson 1.2.83
• mockito 3.5.11
• jdk 1.8.301.09
• osx

try {
    Object a_pojo_object = Mockito.mock(SomePOJO.class);
    JSON.toJSON(a_pojo_object);
} catch (Exception e) {
    e.printStackTrace();
    //logger.error(e.getMessage(), e);
}

com.alibaba.fastjson.JSONException: toJSON error
    at com.alibaba.fastjson.JSON.toJSON(JSON.java:1226)
    at com.alibaba.fastjson.JSON.toJSON(JSON.java:1116)
    at JsonErrTest.testJsonErr(JsonErrTest.java:32)
        ...
Caused by: com.alibaba.fastjson.JSONException: toJSON error
    at com.alibaba.fastjson.JSON.toJSON(JSON.java:1226) ~[fastjson-1.2.83.jar:?]
    at com.alibaba.fastjson.JSON.toJSON(JSON.java:1223) ~[fastjson-1.2.83.jar:?]
    ... 12 more
Caused by: com.alibaba.fastjson.JSONException: toJSON error
    at com.alibaba.fastjson.JSON.toJSON(JSON.java:1226) ~[fastjson-1.2.83.jar:?]
    at com.alibaba.fastjson.JSON.toJSON(JSON.java:1223) ~[fastjson-1.2.83.jar:?]
    at com.alibaba.fastjson.JSON.toJSON(JSON.java:1223) ~[fastjson-1.2.83.jar:?]
    ... 12 more
Caused by: com.alibaba.fastjson.JSONException: toJSON error
    at com.alibaba.fastjson.JSON.toJSON(JSON.java:1226) ~[fastjson-1.2.83.jar:?]
    at com.alibaba.fastjson.JSON.toJSON(JSON.java:1223) ~[fastjson-1.2.83.jar:?]
    at com.alibaba.fastjson.JSON.toJSON(JSON.java:1223) ~[fastjson-1.2.83.jar:?]
    at com.alibaba.fastjson.JSON.toJSON(JSON.java:1223) ~[fastjson-1.2.83.jar:?]
    ... 12 more
long long...

java.lang.reflect.InvocationTargetException
    at sun.reflect.GeneratedMethodAccessor565.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.alibaba.fastjson.util.FieldInfo.get(FieldInfo.java:571)
    at com.alibaba.fastjson.serializer.FieldSerializer.getPropertyValue(FieldSerializer.java:151)
    at com.alibaba.fastjson.serializer.JavaBeanSerializer.getFieldValuesMap(JavaBeanSerializer.java:799)
    at com.alibaba.fastjson.JSON.toJSON(JSON.java:1221)
    at com.alibaba.fastjson.JSON.toJSON(JSON.java:1223)
    at com.alibaba.fastjson.JSON.toJSON(JSON.java:1223)
    at com.alibaba.fastjson.JSON.toJSON(JSON.java:1223)
long long...

java.lang.StackOverflowError
    at sun.nio.cs.UTF_8$Encoder.encodeLoop(UTF_8.java:691)
    at java.nio.charset.CharsetEncoder.encode(CharsetEncoder.java:579)
    at sun.nio.cs.StreamEncoder.implWrite(StreamEncoder.java:271)
    at sun.nio.cs.StreamEncoder.write(StreamEncoder.java:125)
    at java.io.OutputStreamWriter.write(OutputStreamWriter.java:207)
    at java.io.BufferedWriter.flushBuffer(BufferedWriter.java:129)
    at java.io.PrintStream.write(PrintStream.java:526)
    at java.io.PrintStream.print(PrintStream.java:669)
    at java.io.PrintStream.println(PrintStream.java:823)
    at java.lang.Throwable$WrappedPrintStream.println(Throwable.java:749)
    at java.lang.Throwable.printEnclosedStackTrace(Throwable.java:696)
    at java.lang.Throwable.printEnclosedStackTrace(Throwable.java:710)
    at java.lang.Throwable.printEnclosedStackTrace(Throwable.java:710)
    at java.lang.Throwable.printEnclosedStackTrace(Throwable.java:710)
long long...