Support for building with OpenJDK 21

[linghengqian]

Fixes #2269.

Changes proposed in this pull request:

• Support for building with OpenJDK 21.
• Disables a unit test involving lambda on a specific JDK.

[codecov-commenter]

Codecov Report

Merging #2270 (2668b86) into master (d4f7d94) will decrease coverage by 0.05%.
Report is 1 commits behind head on master.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #2270      +/-   ##
============================================
- Coverage     84.46%   84.41%   -0.05%     
+ Complexity     1929     1928       -1     
============================================
  Files           287      287              
  Lines          6341     6341              
  Branches        704      704              
============================================
- Hits           5356     5353       -3     
- Misses          659      661       +2     
- Partials        326      327       +1     

Files Changed	Coverage Δ
...elasticjob/lite/internal/server/ServerService.java	72.34% <ø> (ø)

... and 2 files with indirect coverage changes

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