fix fastjson serialization with generic return type

[cyejing]

What is the purpose of the change

修复fastjson序列的问题，有三层泛型以上时序列化报错 如：A<B>

Brief changelog

修复fastjson序列的问题，有三层泛型以上时序列化报错 如：A<B>

Verifying this change

三层泛型以上 会序列化成JSONArray 或者 JSONObject导致获取对象时发生强转异常
： Class1 cannot be cast to Class2

some issues #3767

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[codecov-io]

Codecov Report

Merging #3771 into master will decrease coverage by 0.04%.
The diff coverage is 100%.

@@             Coverage Diff              @@
##             master    #3771      +/-   ##
============================================
- Coverage     63.59%   63.55%   -0.05%     
  Complexity       71       71              
============================================
  Files           704      704              
  Lines         31063    31063              
  Branches       5037     5037              
============================================
- Hits          19756    19743      -13     
- Misses         9033     9044      +11     
- Partials       2274     2276       +2

Impacted Files	Coverage Δ	Complexity Δ
...common/serialize/fastjson/FastJsonObjectInput.java	100% <100%> (+8%)	0 <0> (ø)	⬇️
...ache/dubbo/remoting/p2p/support/AbstractGroup.java	45.45% <0%> (-11.37%)	0% <0%> (ø)
...e/dubbo/remoting/transport/netty/NettyChannel.java	57.64% <0%> (-4.71%)	0% <0%> (ø)
.../apache/dubbo/remoting/transport/AbstractPeer.java	63.04% <0%> (-4.35%)	0% <0%> (ø)
...dubbo/remoting/exchange/support/DefaultFuture.java	73.46% <0%> (-2.05%)	0% <0%> (ø)
...pache/dubbo/registry/support/AbstractRegistry.java	79.52% <0%> (-1.19%)	0% <0%> (ø)
...bo/rpc/cluster/support/FailbackClusterInvoker.java	70.49% <0%> (+3.27%)	0% <0%> (ø)	⬇️

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[kexianjun]

do not merge, let me check again

[kexianjun]

this work fine for method with generic return type, but when a method has generic parameters, this problem still exists, merge this first and I'll open an issue for the generic parameters