Should_Not_Leak_Connections_Test is flakky

[dkropachev]

It can fail with following error:

Failed Should_Not_Leak_Connections_Test [11 s]
  Error Message:
     Should not exceed a 50% (1.5) more than was previously allocated
Assert.That(arg1, Is.LessThan(arg2))
  Expected: less than 1.5m
  But was:  1.5327489560792127286075724964m

  Stack Trace:
     at NUnit.Framework.Legacy.ClassicAssert.Less(Decimal arg1, Decimal arg2, String message, Object[] args)
   at Cassandra.IntegrationTests.Core.ClientTimeoutTests.Should_Not_Leak_Connections_Test() in /home/runner/work/csharp-driver/csharp-driver/src/Cassandra.IntegrationTests/Core/ClientTimeoutTests.cs:line 380

1)    at NUnit.Framework.Legacy.ClassicAssert.Less(Decimal arg1, Decimal arg2, String message, Object[] args)
   at Cassandra.IntegrationTests.Core.ClientTimeoutTests.Should_Not_Leak_Connections_Test() in /home/runner/work/csharp-driver/csharp-driver/src/Cassandra.IntegrationTests/Core/ClientTimeoutTests.cs:line 380

Investigate what happens there.