Revert "pageserver,safekeeper: disable heap profiling (#10268)"

[erikgrinaker]

This reverts commit b33299d.

Heap profiles weren't the culprit after all.

Touches #10225.

[github-actions]

7227 tests run: 6873 passed, 0 failed, 354 skipped (full report)

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Flaky tests (1)

Postgres 15

• test_physical_replication_config_mismatch_max_locks_per_transaction: release-arm64

Code coverage* (full report)

• functions: 31.2% (8411 of 26961 functions)
• lines: 48.0% (66782 of 139225 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
13bef13 at 2025-01-07T21:20:41.452Z :recycle:}