Reactivate page bench test in CI after ignoring CopyFail error in pageserver

[Bodobolero]

Problem

Testcase page bench test_pageserver_max_throughput_getpage_at_latest_lsn had been deactivated because it was flaky.

We now ignore copy fail error messages like in

neon/test_runner/regress/test_pageserver_getpage_throttle.py

Lines 17 to 20 in 270d3be

	env.pageserver.allowed_errors.append(
	# https://github.com/neondatabase/neon/issues/6925
	r".*query handler for.*pagestream.*failed: unexpected message: CopyFail during COPY.*"
	)

and want to reactivate it to see it it is still flaky

Summary of changes

• reactivate the test in CI
• ignore CopyFail error message during page bench test cases

Checklist before requesting a review

• I have performed a self-review of my code.
• If it is a core feature, I have added thorough tests.
• Do we need to implement analytics? if so did you add the relevant metrics to the dashboard?
• If this PR requires public announcement, mark it with /release-notes label and add several sentences in this section.

Checklist before merging

• Do not forget to reformat commit message to not include the above checklist

[github-actions]

3298 tests run: 3147 passed, 0 failed, 151 skipped (full report)

---

Code coverage* (full report)

• functions: 31.6% (6625 of 20989 functions)
• lines: 48.6% (51485 of 106042 lines)

* collected from Rust tests only

---

_{The comment gets automatically updated with the latest test results
8c6c332 at 2024-06-12T14:08:07.568Z :recycle:}

[bayandin]

To get run benchmarks in the PR, you need to add a run-benchmarks label to it, and they'll run for the next commit

[Bodobolero]

Merging after benchmark5 passed https://github.com/neondatabase/neon/actions/runs/9482825569/job/26129422123?pr=8023
Will need to watch successful runs in CI for some time