[CI] MixedClusterEsqlSpecIT test {where-like.RlikeWithLowerTurnedInsensitive SYNC} failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic #8604 / 8.12.2_bwc
• elasticsearch-periodic #8598 / 8.11.4_bwc
• elasticsearch-periodic #8598 / 8.12.2_bwc
• elasticsearch-periodic #8592 / 8.11.4_bwc
• elasticsearch-periodic #8592 / 8.12.2_bwc
• elasticsearch-periodic #8585 / 8.11.4_bwc

Reproduction Line:

./gradlew ":x-pack:plugin:esql:qa:server:mixed-cluster:v8.12.2#javaRestTest" -Dtests.class="org.elasticsearch.xpack.esql.qa.mixed.MixedClusterEsqlSpecIT" -Dtests.method="test {where-like.RlikeWithLowerTurnedInsensitive SYNC}" -Dtests.seed=47019BC79BEE4A2E -Dtests.bwc=true -Dtests.locale=sc-Latn-IT -Dtests.timezone=Egypt -Druntime.java=24

Applicable branches:
8.19

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

org.elasticsearch.client.ResponseException: method [POST], host [http://[::1]:46273], URI [/_query?format=yaml&pretty=true&error_trace=true], status line [HTTP/1.1 400 Bad Request]
Warnings: [No limit defined, adding default limit of [500]]
---
error:
  root_cause:
  - type: "verification_exception"
    reason: "Found 1 problem\nline 4:18: Unknown function [TO_UPPER], did you mean\
      \ any of [to_ver, to_integer, to_ip, to_str, to_ulong, to_ul]?"
    stack_trace: "org.elasticsearch.xpack.esql.analysis.VerificationException: Found\
      \ 1 problem\nline 4:18: Unknown function [TO_UPPER], did you mean any of [to_ver,\
      \ to_integer, to_ip, to_str, to_ulong, to_ul]?\n\tat org.elasticsearch.xpack.esql.analysis.Analyzer.verify(Analyzer.java:120)\n\
      \tat org.elasticsearch.xpack.esql.analysis.Analyzer.analyze(Analyzer.java:114)\n\
      \tat org.elasticsearch.xpack.esql.session.EsqlSession.lambda$analyzedPlan$2(EsqlSession.java:145)\n\
      \tat org.elasticsearch.xpack.esql.
[truncated]

Issue Reasons:

• [8.19] 3 consecutive failures in step 8.12.2_bwc
• [8.19] 3 consecutive failures in step 8.11.4_bwc
• [8.19] 6 failures in test test {where-like.RlikeWithLowerTurnedInsensitive SYNC} (4.7% fail rate in 129 executions)
• [8.19] 3 failures in step 8.12.2_bwc (100.0% fail rate in 3 executions)
• [8.19] 3 failures in step 8.11.4_bwc (100.0% fail rate in 3 executions)
• [8.19] 4 failures in pipeline elasticsearch-periodic (100.0% fail rate in 4 executions)

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

[elasticsearchmachine]

Pinging @elastic/es-analytical-engine (Team:Analytics)

[fang-xing-esql]

We might need an EsqlCapability here, if it worth running these tests on mixed cluster with much older versions like 8.11 or 8.12, FYI @bpintea.

[dnhatn]

Fixed in #128979