[CI] ThreadPoolMergeExecutorServiceDiskSpaceTests testUnavailableBudgetBlocksNewMergeTasksFromStartingExecution failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic-platform-support #9721 / rhel-9_platform-support-unix
• elasticsearch-pull-request #83498 / part-1
• elasticsearch-intake #26216 / part1
• elasticsearch-periodic #9661 / openjdk17_checkpart1_java-fips-matrix
• elasticsearch-periodic-platform-support #9672 / rocky-9_platform-support-unix
• elasticsearch-pull-request #83119 / part-1
• elasticsearch-periodic-platform-support #9651 / sles-12_platform-support-unix
• elasticsearch-periodic-platform-support #9623 / oraclelinux-8_platform-support-unix
• elasticsearch-periodic-platform-support #9616 / oraclelinux-7_platform-support-unix
• elasticsearch-periodic #9591 / graalvm-ce17_checkpart1_java-matrix

Reproduction Line:

./gradlew ":server:test" --tests "org.elasticsearch.index.engine.ThreadPoolMergeExecutorServiceDiskSpaceTests.testUnavailableBudgetBlocksNewMergeTasksFromStartingExecution" -Dtests.seed=7525F777614926 -Dtests.locale=dsb-DE -Dtests.timezone=Etc/GMT+10 -Druntime.java=24

Applicable branches:
8.19

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

org.mockito.exceptions.verification.NeverWantedButInvoked: 
mergeTask.schedule();
Never wanted here:
-> at org.elasticsearch.index.engine.ThreadPoolMergeExecutorServiceDiskSpaceTests.lambda$testUnavailableBudgetBlocksNewMergeTasksFromStartingExecution$39(ThreadPoolMergeExecutorServiceDiskSpaceTests.java:850)
But invoked here:
-> at org.elasticsearch.index.engine.ThreadPoolMergeExecutorService.lambda$enqueueMergeTaskExecution$11(ThreadPoolMergeExecutorService.java:330) with arguments: []

Issue Reasons:

• [8.19] 13 failures in test testUnavailableBudgetBlocksNewMergeTasksFromStartingExecution (1.9% fail rate in 702 executions)
• [8.19] 3 failures in step part-1 (4.2% fail rate in 71 executions)
• [8.19] 2 failures in step part1 (5.7% fail rate in 35 executions)
• [8.19] 2 failures in step sles-12_platform-support-unix (11.1% fail rate in 18 executions)
• [8.19] 6 failures in pipeline elasticsearch-periodic-platform-support (31.6% fail rate in 19 executions)
• [8.19] 3 failures in pipeline elasticsearch-pull-request (4.3% fail rate in 69 executions)
• [8.19] 2 failures in pipeline elasticsearch-intake (5.7% fail rate in 35 executions)
• [8.19] 2 failures in pipeline elasticsearch-periodic (11.1% fail rate in 18 executions)

Note:
This issue was created using new test triage automation. Please report issues or feedback to es-delivery.

[elasticsearchmachine]

Pinging @elastic/es-distributed-indexing (Team:Distributed Indexing)

[albertzaharovits]

Addressed when #132020 is backported to 8.19.

[albertzaharovits]

Closing since #132269 has now been merged.