Fix flaky test RemoteIndexRecoveryIT.testRerouteRecovery

[sachinpkale]

Description

• IndexRecoveryIT.testRerouteRecovery triggers shard movement and verifies few details while recovery is in progress. It also slows down recovery to make sure that shard is not moved before we assert.
• When we extended RemoteIndexRecoveryIT extends IndexRecoveryIT`, we reduced number of docs to be ingested by 5x (this is to decrease test run time as latency of ingestion is higher with remote store enabled).

• OpenSearch/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteIndexRecoveryIT.java

  Lines 67 to 70 in c06f53e

  	@Override
  	protected int numDocs() {
  	return randomIntBetween(100, 200);
  	}

• But we did not slowed down recovery by 5x. This leads to flaky behaviour in the test where recovery completes before we check recovery stats.
• To avoid the flakiness, in this PR, we have slowed down recovery by 5X.

Related Issues

• [AUTOCUT] Gradle Check Flaky Test Report for RemoteIndexRecoveryIT #14323

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 3a2e2f3: 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 3a2e2f3: 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?