RFR: 8348829: Remove ObjectMonitor perf counters

[David Holmes]

On Tue, 28 Jan 2025 09:57:43 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> See bug for more discussion. I believe these counters are useless and come with more trouble than their worth.

Assuming CSR request confirms desirability of deleting these perf counters, the actual deletion seems good. Thanks

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Marked as reviewed by dholmes (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/23326#pullrequestreview-2583016408