[Discover] Unskip Discover large field number test

[kertal]

Summary

Unskips Discover large field number test, by splitting the fixtures with a doc containing 10.000 fields to 3 docs. So there's no more occasional 'circuit_breaking_exception' of Elasticsearch. Furthermore improves and speeds up the test by providing an index pattern in the fixtures, so it's no longer necessary to "manually" create the index pattern in index management.

Fixes #96113

Flaky test runner https://kibana-ci.elastic.co/job/kibana+flaky-test-suite-runner/1675/

Checklist

• Unit or functional tests were updated or added to match the most common scenarios

[kertal]

@elasticmachine merge upstream

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)

[kertal]

@elasticmachine merge upstream

[LeeDr]

This test had been passing for a long time. What caused it to start failing? Users are very frequently asking about indices with very large field counts. This seems like a regression if this test now fails.

[LeeDr]

hmm, I was actually thinking about test kibana\test\functional\apps\management_test_huge_fields.js but that one uses the same data and is also skipped. For the same reason I think? Still seems like a regression.

[kertal]

@LeeDr it seems to be an issue with Elasticsearch memory usage:

[00:32:18] │ info [o.e.c.m.MetadataMappingService] [kibana-ci-immutable-ubuntu-16-tests-xxl-1622098084918717614] [testhuge/w1UtHxqrQ62_lsWyBr4_jA] update_mapping [_doc]
[00:32:19] │ info [o.e.i.b.HierarchyCircuitBreakerService] [kibana-ci-immutable-ubuntu-16-tests-xxl-1622098084918717614] attempting to trigger G1GC due to high heap usage [1047026976]
[00:32:19] │ info [o.e.i.b.HierarchyCircuitBreakerService] [kibana-ci-immutable-ubuntu-16-tests-xxl-1622098084918717614] GC did not bring memory usage down, before [1047026976], after [1055780592], allocations [4], duration [12]

[kertal]

@elasticmachine merge upstream

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: 4f19280
• Storybooks Preview

Metrics [docs]

✅ unchanged

History

• 💚 Build #133064 succeeded 6fde6c9
• 💚 Build #132920 succeeded 94a36a3
• 💚 Build #132677 succeeded 5a82b44
• 💚 Build #132652 succeeded 43271ed
• 💚 Build #129131 succeeded cab886e

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream

cc @kertal

[dimaanj]

Code LGTM!

[kibanamachine]

💚 Backport successful

Status	Branch	Result
✅	7.x

This backport PR will be merged automatically after passing CI.