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

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic #8683 / 8.11.4_bwc
• elasticsearch-periodic #8683 / 8.12.2_bwc
• elasticsearch-periodic #8677 / 8.12.2_bwc
• elasticsearch-periodic #8671 / 8.11.4_bwc
• elasticsearch-periodic #8671 / 8.12.2_bwc
• elasticsearch-periodic #8665 / 8.11.4_bwc
• elasticsearch-periodic #8659 / 8.12.2_bwc
• elasticsearch-periodic #8659 / 8.11.4_bwc
• elasticsearch-periodic #8653 / 8.12.2_bwc
• elasticsearch-periodic #8653 / 8.11.4_bwc

Reproduction Line:

./gradlew ":x-pack:plugin:esql:qa:server:mixed-cluster:v8.11.4#javaRestTest" -Dtests.class="org.elasticsearch.xpack.esql.qa.mixed.MixedClusterEsqlSpecIT" -Dtests.method="test {where-like.RlikeWithLowerConflictingFolded SYNC}" -Dtests.seed=30F14AB6C7AD2ECF -Dtests.bwc=true -Dtests.locale=ar-OM -Dtests.timezone=Etc/GMT-4 -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]:35413], URI [/_query?format=smile&pretty=true&error_trace=true], status line [HTTP/1.1 400 Bad Request]
Warnings: [No limit defined, adding default limit of [500]]
:)
�ú�errorú�root_causeøú�typeUverification_exception�reasonàFound 1 problem
line 4:9: Unknown function [TO_UPPER], did you mean any of [to_ver, to_integer, to_ip, to_str, to_ulong, to_ul]?ü�stack_traceäorg.elasticsearch.xpack.esql.analysis.VerificationException: Found 1 problem
line 4:9: Unknown function [TO_UPPER], did you mean any of [to_ver, to_integer, to_ip, to_str, to_ulong, to_ul]?
	at org.elasticsearch.xpack.esql.analysis.Analyzer.verify(Analyzer.java:113)
	at org.elasticsearch.xpack.esql.analysis.Analyzer.analyze(Analyzer.java:107)
	at org.elasticsearch.xpack.esql.session.EsqlSession.lambda$analyzedPlan$2(EsqlSession.java:143)
	at org.elasticsearch.xpack.esql.session.EsqlSession.lambda$preAnalyze$5(EsqlSession.java:168)
	at org.elasticsea
[truncated]

Issue Reasons:

• [8.19] 3 consecutive failures in step 8.12.2_bwc
• [8.19] 23 failures in test test {where-like.RlikeWithLowerConflictingFolded SYNC} (4.3% fail rate in 540 executions)
• [8.19] 13 failures in step 8.11.4_bwc (76.5% fail rate in 17 executions)
• [8.19] 10 failures in step 8.12.2_bwc (58.8% fail rate in 17 executions)
• [8.19] 16 failures in pipeline elasticsearch-periodic (94.1% fail rate in 17 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)

[luigidellaquila]

This just needs to be excluded in v 8.11-12: TO_LOWER was added in v 8.13