GH-114911: use time.perf_counter in Stopwatch

[chris-eibl]

Use perf_counter in Stopwatch.

I temporarily added

    def test_denial_of_service_prevented_str_to_int_many(self):
        for i in range(1000):
            self.test_denial_of_service_prevented_str_to_int()

to test_int.py. With process_time it always failed, with perf_counter it always succeeded.

I think this is a skip news?

• Issue: [Windows] test_int.test_denial_of_service failed: took 15ms #114911

[AA-Turner]

Looks reasonable.

A

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @encukou for commit 39eb532 🤖

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https://buildbot.python.org/all/#/grid?branch=refs%2Fpull%2F131469%2Fmerge

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