gh-142434: Use ppoll() if available in select.poll

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• Issue: select.poll.poll should use ppoll when it's available #142434

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Example:

import socket, time, select

s1, s2 = socket.socketpair()
poll = select.poll()
poll.register(s1, select.POLLIN)
ms = 1e-6
start_time = time.perf_counter()
poll.poll(ms)
dt = time.perf_counter() - start_time
print(f"dt: {dt*1e6:.1f} us")
s1.close()
s2.close()

Results on Linux:

• Without this change: dt: 1099.4 us
• With this change: dt: 61.7 us => 18x better resolution