bugfix: fix mysql connection unable to release

[funky-eyes]

Ⅰ. Describe what this PR did

fix mysql connect unable to release bug

Ⅱ. Does this pull request fix one issue?

fixes #2034
fixes #2035

Ⅲ. Why don't you add test cases (unit test/integration test)?

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[zjinlei]

LGTM

[codecov-io]

Codecov Report

Merging #2037 into develop will decrease coverage by 0.01%.
The diff coverage is 100%.

@@             Coverage Diff              @@
##             develop   #2037      +/-   ##
============================================
- Coverage      55.01%     55%   -0.02%     
+ Complexity      2474    2472       -2     
============================================
  Files            444     444              
  Lines          14793   14794       +1     
  Branches        1746    1746              
============================================
- Hits            8138    8137       -1     
+ Misses          5909    5908       -1     
- Partials         746     749       +3

Impacted Files	Coverage Δ	Complexity Δ
...tasource/sql/struct/cache/MysqlTableMetaCache.java	81.08% <100%> (+0.17%)	11 <0> (ø)	⬇️
...in/java/io/seata/server/session/GlobalSession.java	84.54% <0%> (-0.49%)	67% <0%> (-1%)
...o/seata/server/coordinator/DefaultCoordinator.java	48.01% <0%> (-0.4%)	27% <0%> (-1%)
...server/store/file/FileTransactionStoreManager.java	56.19% <0%> (-0.32%)	29% <0%> (ø)
...very/registry/zk/ZookeeperRegisterServiceImpl.java	63.7% <0%> (+0.8%)	24% <0%> (ø)	⬇️

[l81893521]

LGTM

[slievrly]

@a364176773 great found. Does Oracle have the same problem?

[funky-eyes]

@a364176773 great found. Does Oracle have the same problem?

Not yet discovered