fix(pageserver): ensure tenant harness has different names

[skyzh]

Problem

as title

Summary of changes

rename the tenant test harness name

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]

2940 tests run: 2823 passed, 0 failed, 117 skipped (full report)

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Flaky tests (1)

Postgres 15

• test_delete_timeline_client_hangup: debug

Code coverage* (full report)

• functions: 32.7% (6905 of 21115 functions)
• lines: 50.1% (54137 of 108064 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
aab59d3 at 2024-06-28T17:24:58.614Z :recycle:}