fix bugs detected by doubao

[Wangzy455]

What this PR does: for https://github.com/apache/incubator-seata-go/issues/879

Which issue(s) this PR fixes: fix some issue about getty

[codecov-commenter]

Codecov Report

:x: Patch coverage is 0% with 27 lines in your changes missing coverage. Please review. :white_check_mark: Project coverage is 56.41%. Comparing base (b18bcb0) to head (0b8fa14).

Files with missing lines	Patch %	Lines
pkg/remoting/getty/listener.go	0.00%	21 Missing :warning:
pkg/remoting/getty/session_manager.go	0.00%	5 Missing :warning:
pkg/remoting/getty/getty_remoting.go	0.00%	1 Missing :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #898      +/-   ##
==========================================
- Coverage   56.49%   56.41%   -0.08%     
==========================================
  Files         266      266              
  Lines       17484    17511      +27     
==========================================
+ Hits         9877     9879       +2     
- Misses       6772     6798      +26     
+ Partials      835      834       -1     

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[AlexStocks]

would you like to add some uts for this PR?

[Wangzy455]

would you like to add some uts for this PR?

OK, I will improve the unit test to verify the newly added reconnection method

[Wangzy455]

would you like to add some uts for this PR?

OK, I will improve the unit test to verify the newly added reconnection method

I removed the reconnect method and only kept the resource cleanup part.

[LucienShen-Liu]

Please handle the above comments.