fix the constant name in LFUCache

[xuekg]

What is the purpose of the change

fix the constant name in LFUCache

Brief changelog

ensure the legibility of code

Verifying this change

XXXXX

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[codecov-io]

Codecov Report

Merging #7094 (5f6cd17) into master (f7127c7) will decrease coverage by 0.07%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##             master    #7094      +/-   ##
============================================
- Coverage     59.23%   59.15%   -0.08%     
+ Complexity      510      506       -4     
============================================
  Files          1028     1028              
  Lines         41525    41525              
  Branches       6038     6038              
============================================
- Hits          24597    24565      -32     
- Misses        14167    14195      +28     
- Partials       2761     2765       +4     

Impacted Files	Coverage Δ	Complexity Δ
...n/java/org/apache/dubbo/common/utils/LFUCache.java	79.61% <100.00%> (ø)	0.00 <0.00> (ø)
...he/dubbo/common/threadpool/ThreadlessExecutor.java	52.17% <0.00%> (-10.87%)	0.00% <0.00%> (ø%)
...che/dubbo/remoting/transport/mina/MinaChannel.java	39.47% <0.00%> (-10.53%)	15.00% <0.00%> (-1.00%)
.../apache/dubbo/rpc/protocol/AsyncToSyncInvoker.java	62.06% <0.00%> (-10.35%)	0.00% <0.00%> (ø%)
...e/dubbo/remoting/transport/netty/NettyChannel.java	55.68% <0.00%> (-4.55%)	20.00% <0.00%> (-1.00%)
...dubbo/remoting/exchange/support/DefaultFuture.java	74.35% <0.00%> (-4.28%)	0.00% <0.00%> (ø%)
...he/dubbo/remoting/transport/netty/NettyServer.java	70.17% <0.00%> (-3.51%)	8.00% <0.00%> (-1.00%)
...pache/dubbo/registry/support/AbstractRegistry.java	77.77% <0.00%> (-3.34%)	0.00% <0.00%> (ø%)
...a/org/apache/dubbo/monitor/dubbo/DubboMonitor.java	86.66% <0.00%> (-2.86%)	16.00% <0.00%> (-1.00%)
...rg/apache/dubbo/common/timer/HashedWheelTimer.java	62.88% <0.00%> (-0.69%)	0.00% <0.00%> (ø%)
... and 7 more

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[ralf0131]

LGTM.