bugfix: xid would be duplicate in cluster mode

[Justice-love]

Ⅰ. Describe what this PR did

Ⅱ. Does this pull request fix one issue?

fixes #1455

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

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[codecov-io]

Codecov Report

Merging #1456 into develop will increase coverage by <.01%.
The diff coverage is 33.33%.

@@              Coverage Diff              @@
##             develop    #1456      +/-   ##
=============================================
+ Coverage      45.67%   45.68%   +<.01%     
  Complexity      1664     1664              
=============================================
  Files            345      345              
  Lines          12673    12675       +2     
  Branches        1593     1593              
=============================================
+ Hits            5789     5790       +1     
- Misses          6235     6236       +1     
  Partials         649      649

Impacted Files	Coverage Δ	Complexity Δ
server/src/main/java/io/seata/server/Server.java	0% <0%> (ø)	0 <0> (ø)	⬇️
...src/main/java/io/seata/server/ParameterParser.java	55.17% <50%> (-0.39%)	6 <0> (ø)

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[slievrly]

LGTM

[sharajava]

okey to me