Add : delete mock json in test case of apollo

[zouyx]

What this PR does:

delete mock json in test case of apollo when cases finished

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

[codecov-io]

Codecov Report

Merging #304 into develop will decrease coverage by 0.75%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop     #304      +/-   ##
===========================================
- Coverage    66.58%   65.82%   -0.76%     
===========================================
  Files          112      113       +1     
  Lines         7182     7239      +57     
===========================================
- Hits          4782     4765      -17     
- Misses        1934     2005      +71     
- Partials       466      469       +3

Impacted Files	Coverage Δ
protocol/dubbo/pool.go	59.51% <0%> (-15.13%)	⬇️
protocol/dubbo/listener.go	50.28% <0%> (-10.41%)	⬇️
protocol/dubbo/codec.go	70.27% <0%> (-5.41%)	⬇️
protocol/dubbo/readwriter.go	68.29% <0%> (-2.44%)	⬇️
remoting/zookeeper/listener.go	46.9% <0%> (-1.04%)	⬇️
remoting/zookeeper/client.go	63.87% <0%> (-0.58%)	⬇️
filter/impl/hystrix_filter.go
filter/impl/active_filter.go
filter/impl/graceful_shutdown_filter.go
filter/impl/token_filter.go
... and 31 more

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[zouyx]

@flycash @fangyincheng check again pls.

[fangyincheng]

LGTM