Fix the numeric overflow bug of ping response data in the cluster module

[sczyh30]

Signed-off-by: Eric Zhao sczyh16@gmail.com

Describe what this PR does / why we need it

Fix the bug that the ping response data (of byte type) in the default cluster transport implementation might overflow.

Does this pull request fix one issue?

Fixes #843

Describe how you did it

Change type of cluster ping data response from byte to int. Both PingResponseDataWriter and PingResponseDataDecoder have been modified.

The PingResponseDataDecoder will be compatible with old versions:

• For old token servers and new clients, the client will parse the ping response as byte.
• Old clients will be compatible with token servers, but overflow will still happen.

Describe how to verify it

Run the test cases.

Special notes for reviews

NONE

[codecov-io]

Codecov Report

Merging #844 into master will increase coverage by 0.08%.
The diff coverage is 80%.

@@             Coverage Diff              @@
##             master     #844      +/-   ##
============================================
+ Coverage     41.73%   41.82%   +0.08%     
- Complexity     1383     1389       +6     
============================================
  Files           305      305              
  Lines          8807     8810       +3     
  Branches       1188     1190       +2     
============================================
+ Hits           3676     3685       +9     
+ Misses         4677     4670       -7     
- Partials        454      455       +1

Impacted Files	Coverage Δ	Complexity Δ
...ster/server/codec/data/PingResponseDataWriter.java	60% <100%> (+60%)	2 <0> (+2)	⬆️
...ter/client/codec/data/PingResponseDataDecoder.java	71.42% <75%> (+71.42%)	3 <2> (+3)	⬆️
...ava/com/alibaba/csp/sentinel/node/ClusterNode.java	100% <0%> (+4.76%)	8% <0%> (+1%)	⬆️

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[CarpenterLee]

LGTM