DRIVERS-2774 Delete pool-clear-interrupt-immediately (#1487)

SDAM already have tests covering the functionality, for example
https://github.com/mongodb/specifications/blob/fe95775ad9f4d0599c4b5e02516181d963bc2626/source/server-discovery-and-monitoring/tests/unified/interruptInUse-pool-clear.yml#L23.
Given that currently pool-clear-interrupt-immediately cannot possibly work in Python and requires modifying the test runner, it seems better to remove the test.

Author: stIncMale