Do not acquire a read lock twice on tidyStatusLock during tidy-status

[stevendpclark]

Description

A deadlock can occur when we are reading the PKI tidy-status endpoint. This was introduced within PR28488 so no version of Vault that was released contains this issue.

The deadlock occurs when

1. The tidy-status api is called and acquires the read lock on tidyStatusLock at the top of pathTidyStatusRead line 1689
2. A blocking Lock call is performed against tidyStatusLock say within startTidyOperation line 999
3. The call to b.getLastAutoTidyTime() on line 1727 attempts to re-acquire the read lock on tidyStatusLock. Normally this works as both calls are requesting read locks so it goes through but once a Write lock request is pending we will deadlock.

TODO only if you're a HashiCorp employee

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[raskchanky]

[github-actions]

CI Results:
All Go tests succeeded! ✅

[github-actions]

Build Results:
All builds succeeded! ✅

[kubawi]

LGTM, thanks Steve!

[stevendpclark]

Thanks all for the reviews!