[CI] ThreadPoolMergeExecutorServiceDiskSpaceTests testUnavailableBudgetBlocksNewMergeTasksFromStartingExecution failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic-platform-support #8970 / ubuntu-2404_platform-support-unix
• elasticsearch-pull-request #77461 / part-1
• elasticsearch-periodic-platform-support #8963 / amazonlinux-2_platform-support-aws
• elasticsearch-pull-request #77321 / part-1
• elasticsearch-periodic-platform-support #8950 / ubuntu-2004_platform-support-unix
• elasticsearch-periodic #8935 / openjdk21_checkpart1_java-matrix
• elasticsearch-intake #24479 / part1
• elasticsearch-periodic-platform-support #8938 / amazonlinux-2_platform-support-aws
• elasticsearch-periodic-platform-support #8932 / ubuntu-2404_platform-support-unix
• elasticsearch-periodic-platform-support #8932 / ubuntu-2004_platform-support-unix

Reproduction Line:

./gradlew ":server:test" --tests "org.elasticsearch.index.engine.ThreadPoolMergeExecutorServiceDiskSpaceTests.testUnavailableBudgetBlocksNewMergeTasksFromStartingExecution" -Dtests.seed=D9E0BBDCE2C99468 -Dtests.locale=is-IS -Dtests.timezone=Asia/Macao -Druntime.java=24

Applicable branches:
8.19

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

java.lang.AssertionError: 
Expected: is <true>
     but: was <false>

Issue Reasons:

• [8.19] 32 failures in test testUnavailableBudgetBlocksNewMergeTasksFromStartingExecution (3.5% fail rate in 909 executions)
• [8.19] 3 failures in step ubuntu-2404_platform-support-unix (14.3% fail rate in 21 executions)
• [8.19] 7 failures in step part-1 (5.9% fail rate in 118 executions)
• [8.19] 3 failures in step part1 (4.1% fail rate in 73 executions)
• [8.19] 3 failures in step ubuntu-2004_platform-support-unix (16.7% fail rate in 18 executions)
• [8.19] 2 failures in step openjdk17_checkpart1_java-matrix (10.0% fail rate in 20 executions)
• [8.19] 2 failures in step ubuntu-2004-aarch64_checkpart1_platform-support-arm (10.0% fail rate in 20 executions)
• [8.19] 2 failures in step amazonlinux-2_platform-support-aws (10.0% fail rate in 20 executions)
• [8.19] 12 failures in pipeline elasticsearch-periodic-platform-support (54.5% fail rate in 22 executions)
• [8.19] 7 failures in pipeline elasticsearch-pull-request (7.1% fail rate in 99 executions)
• [8.19] 3 failures in pipeline elasticsearch-intake (4.1% fail rate in 73 executions)
• [8.19] 4 failures in pipeline elasticsearch-periodic (19.0% fail rate in 21 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)

[elasticsearchmachine]

This has been muted on branch main

Mute Reasons:

• [main] 2 consecutive failures in step ubuntu-2204_platform-support-unix
• [main] 4 failures in test testUnavailableBudgetBlocksNewMergeTasksFromStartingExecution (4.3% fail rate in 92 executions)
• [main] 2 failures in step ubuntu-2204_platform-support-unix (66.7% fail rate in 3 executions)
• [main] 2 failures in pipeline elasticsearch-periodic-platform-support (66.7% fail rate in 3 executions)

Build Scans:

• elasticsearch-intake #23795 / part1
• elasticsearch-periodic-platform-support #8676 / almalinux-8-aarch64_checkpart1_platform-support-arm
• elasticsearch-periodic-platform-support #8676 / ubuntu-2204_platform-support-unix
• elasticsearch-periodic-platform-support #8670 / ubuntu-2204_platform-support-unix

[afoucret]

This test is also failing on branch 8.19.
Should we mute it also in this branch?