clear unused import

[freekry]

clear unused import.

[codecov-io]

Codecov Report

Merging #4976 into master will decrease coverage by 0.08%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #4976      +/-   ##
============================================
- Coverage     64.03%   63.94%   -0.09%     
+ Complexity      453      450       -3     
============================================
  Files           769      769              
  Lines         33160    33160              
  Branches       5230     5230              
============================================
- Hits          21233    21204      -29     
- Misses         9511     9533      +22     
- Partials       2416     2423       +7

Impacted Files	Coverage Δ	Complexity Δ
.../apache/dubbo/qos/protocol/QosProtocolWrapper.java	70.73% <0%> (-12.2%)	0% <0%> (ø)
...e/dubbo/remoting/transport/netty/NettyChannel.java	54.11% <0%> (-8.24%)	19% <0%> (-2%)
...apache/dubbo/rpc/protocol/dubbo/FutureAdapter.java	53.84% <0%> (-7.7%)	0% <0%> (ø)
...bbo/registry/support/ProviderConsumerRegTable.java	80.48% <0%> (-4.88%)	0% <0%> (ø)
.../apache/dubbo/remoting/transport/AbstractPeer.java	63.04% <0%> (-4.35%)	0% <0%> (ø)
...ache/dubbo/rpc/protocol/ProtocolFilterWrapper.java	85% <0%> (-3.34%)	0% <0%> (ø)
...dubbo/metadata/support/AbstractMetadataReport.java	71.09% <0%> (-1.74%)	0% <0%> (ø)
...he/dubbo/registry/multicast/MulticastRegistry.java	67.87% <0%> (-1.36%)	0% <0%> (ø)
...a/org/apache/dubbo/monitor/dubbo/DubboMonitor.java	89.71% <0%> (-0.94%)	16% <0%> (-1%)
...g/apache/dubbo/registry/consul/ConsulRegistry.java	61.87% <0%> (-0.63%)	29% <0%> (ø)
... and 1 more

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[htynkn]

For unused import, we have checkstyle for main source code, but it haven't apply for test code.
Thanks for your PR