Replace explicit type conversion with instanceof pattern variable in org.opensearch.search package

[gaobinlong]

Description

Use the modern instanceof pattern variables instead of explicit type conversions in the package org.opensearch.search, this can improve the code readability and reduce potential ClassCastException risks.

Most code are generated by LLM, and I checked them manually and reverted the unnecessary and wrong changes.

Related Issues

No issue, just mentioned this in a previous PR.

Check List

- [ ] Functionality includes testing.
- [ ] API changes companion pull request created, if applicable.
- [ ] Public documentation issue/PR created, if applicable.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[sandeshkr419]

LGTM!

Thanks for picking this up!
I have been procrastinating to do this myself.

[github-actions]

❌ Gradle check result for 0c92e9f: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[gaobinlong]

❌ Gradle check result for 0c92e9f: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

Known issue: #15821

[github-actions]

✅ Gradle check result for 0c92e9f: SUCCESS

[codecov]

Codecov Report

❌ Patch coverage is 50.74627% with 99 lines in your changes missing coverage. Please review.
✅ Project coverage is 73.12%. Comparing base (f1a1e9f) to head (1b9cf48).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
.../search/aggregations/BucketCollectorProcessor.java	30.76%	17 Missing and 10 partials ⚠️
...h/search/query/rewriters/TermsMergingRewriter.java	50.00%	2 Missing and 5 partials ⚠️
...search/suggest/phrase/PhraseSuggestionBuilder.java	12.50%	5 Missing and 2 partials ⚠️
...ch/fetch/subphase/highlight/CustomQueryScorer.java	0.00%	3 Missing and 3 partials ⚠️
...a/org/opensearch/search/sort/FieldSortBuilder.java	33.33%	2 Missing and 4 partials ⚠️
...arch/search/pipeline/ProcessorExecutionDetail.java	44.44%	2 Missing and 3 partials ⚠️
...n/java/org/opensearch/search/SearchSortValues.java	33.33%	2 Missing and 2 partials ⚠️
...rch/query/rewriters/BooleanFlatteningRewriter.java	55.55%	0 Missing and 4 partials ⚠️
...earch/query/rewriters/MatchAllRemovalRewriter.java	60.00%	0 Missing and 4 partials ⚠️
...earch/aggregations/PipelineAggregationBuilder.java	25.00%	1 Missing and 2 partials ⚠️
... and 21 more

Additional details and impacted files

@@            Coverage Diff            @@
##               main   #19714   +/-   ##
=========================================
  Coverage     73.11%   73.12%           
+ Complexity    70911    70899   -12     
=========================================
  Files          5735     5735           
  Lines        324655   324609   -46     
  Branches      46962    46962           
=========================================
- Hits         237376   237373    -3     
+ Misses        68173    68092   -81     
- Partials      19106    19144   +38     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[github-actions]

❌ Gradle check result for e277f97: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[github-actions]

❌ Gradle check result for e277f97: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[github-actions]

❌ Gradle check result for e277f97: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[sandeshkr419]

@gaobinlong Can you please rebase with main once - bwc should succeed then.

[github-actions]

❌ Gradle check result for 1b9cf48: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[github-actions]

✅ Gradle check result for 1b9cf48: SUCCESS