[CI] Fixes flaky early stopping test

[zachgk]

This changes the test from requiring the early stopping at a particular epoch to ensuring that it stops early due to time constraints. This should help reduce the chances of being flaky due to race conditions.

[codecov-commenter]

Codecov Report

Attention: 1365 lines in your changes are missing coverage. Please review.

Comparison is base (bb5073f) 72.08% compared to head (6c27157) 72.30%.
Report is 917 commits behind head on master.

Files	Patch %	Lines
...va/ai/djl/modality/nlp/generate/TextGenerator.java	2.81%	276 Missing ⚠️
.../java/ai/djl/modality/nlp/generate/SeqBatcher.java	0.75%	132 Missing ⚠️
...ity/nlp/generate/ContrastiveSeqBatchScheduler.java	2.97%	98 Missing ⚠️
...i/djl/modality/nlp/generate/SeqBatchScheduler.java	9.83%	55 Missing ⚠️
.../java/ai/djl/modality/cv/BufferedImageFactory.java	40.96%	47 Missing and 2 partials ⚠️
...a/ai/djl/modality/nlp/generate/StepGeneration.java	2.04%	48 Missing ⚠️
api/src/main/java/ai/djl/ndarray/NDArray.java	43.42%	39 Missing and 4 partials ⚠️
...n/java/ai/djl/modality/cv/output/CategoryMask.java	22.00%	39 Missing ⚠️
...i/src/main/java/ai/djl/ndarray/NDArrayAdapter.java	71.21%	31 Missing and 7 partials ⚠️
.../cv/translator/SemanticSegmentationTranslator.java	37.50%	35 Missing ⚠️
... and 76 more

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Additional details and impacted files

@@             Coverage Diff              @@
##             master    #2866      +/-   ##
============================================
+ Coverage     72.08%   72.30%   +0.21%     
- Complexity     5126     7163    +2037     
============================================
  Files           473      708     +235     
  Lines         21970    31915    +9945     
  Branches       2351     3314     +963     
============================================
+ Hits          15838    23077    +7239     
- Misses         4925     7260    +2335     
- Partials       1207     1578     +371     

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