bugfix: EnhancedServiceLoader may be appears load class error

[jsbxyyx]

Ⅰ. Describe what this PR did

Ⅱ. Does this pull request fix one issue?

fixes #1517

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

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[xingfudeshi]

please change the title.

[codecov-io]

Codecov Report

Merging #1518 into develop will increase coverage by <.01%.
The diff coverage is 50%.

@@              Coverage Diff              @@
##             develop    #1518      +/-   ##
=============================================
+ Coverage      46.43%   46.44%   +<.01%     
  Complexity      1691     1691              
=============================================
  Files            347      347              
  Lines          12707    12709       +2     
  Branches        1588     1588              
=============================================
+ Hits            5901     5903       +2     
- Misses          6167     6168       +1     
+ Partials         639      638       -1

Impacted Files	Coverage Δ	Complexity Δ
.../io/seata/common/loader/EnhancedServiceLoader.java	62.29% <50%> (-0.21%)	24 <0> (ø)
...server/store/file/FileTransactionStoreManager.java	47.38% <0%> (+0.34%)	19% <0%> (ø)	⬇️

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[slievrly]

LGTM

[xingfudeshi]

LGTM.