Flaky test : Don't use async repo for SplitIndex and wait for translo…

[gbbafna]

…g file deletion

Description

1. Use sync repo for RemoteSplitIndex IT
2. Wait for file deletion for remote store cases as it is an async flow .

Related Issues

Resolves #14296

Check List

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

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[github-actions]

❌ Gradle check result for ec13798: 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 d02fc4d: SUCCESS

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 71.87%. Comparing base (48634bd) to head (27935b1).
Report is 19 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #15107      +/-   ##
============================================
+ Coverage     71.82%   71.87%   +0.04%     
- Complexity    62778    62829      +51     
============================================
  Files          5169     5169              
  Lines        294646   294665      +19     
  Branches      42610    42616       +6     
============================================
+ Hits         211644   211801     +157     
+ Misses        65573    65453     -120     
+ Partials      17429    17411      -18     

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[github-actions]

✅ Gradle check result for 27935b1: SUCCESS

[opensearch-trigger-bot]

The backport to 2.x failed:

The process '/usr/bin/git' failed with exit code 128

To backport manually, run these commands in your terminal:

# Navigate to the root of your repository
cd $(git rev-parse --show-toplevel)
# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/OpenSearch/backport-2.x 2.x
# Navigate to the new working tree
pushd ../.worktrees/OpenSearch/backport-2.x
# Create a new branch
git switch --create backport/backport-15107-to-2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 875b603ccead43b5302195c71208e758af1848c2
# Push it to GitHub
git push --set-upstream origin backport/backport-15107-to-2.x
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/OpenSearch/backport-2.x

Then, create a pull request where the base branch is 2.x and the compare/head branch is backport/backport-15107-to-2.x.