Fix flaky TestIcebergFileMetastoreCreateTableFailure

[ebyhr]

Description

Error:  io.trino.plugin.iceberg.catalog.file.TestIcebergFileMetastoreCreateTableFailure.testCreateTableFailureMetadataCleanedUp -- Time elapsed: 0.014 s <<< FAILURE!
java.lang.AssertionError: 

Expecting throwable message:
  "Test-simulated metastore runtime exception"
to contain:
  "Test-simulated metastore schema not found exception"
but did not.

https://github.com/trinodb/trino/actions/runs/7010135638/job/19071177674

Release notes

(x) This is not user-visible or is docs only, and no release notes are required.

[findepi]

This test used to be marked @Test(singleThreaded = true) // testException is a shared mutable state and it got lost when migrating to JUnit. thanks @ebyhr for adding it back

I fully understand that it is obvious that mistakes may happen, but maybe there is a way to check if there are any other cases like this one?