Fix empty node issue after master failover

[BalaBalaYi]

What changes were proposed in this pull request?

Re add relaunch worker node info back to job_nodes in JobManager during 'list' operation.

Why are the changes needed?

Fix empty node issue after master failover.

Does this PR introduce any user-facing change?

No.

How was this patch tested?

UT and training(with worker failover + master failover).

[codecov]

Codecov Report

Attention: Patch coverage is 92.85714% with 1 line in your changes missing coverage. Please review.

Project coverage is 80.45%. Comparing base (a55b1cf) to head (2e30831).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
dlrover/python/master/node/dist_job_manager.py	90.90%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1317      +/-   ##
==========================================
- Coverage   80.46%   80.45%   -0.01%     
==========================================
  Files         222      222              
  Lines       20728    20740      +12     
==========================================
+ Hits        16678    16687       +9     
- Misses       4050     4053       +3     

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[samplise]

lgtm