Tests: Improve stability for AbortOnConnectFailTests

[NickCraver]

These had a lot timeout for runtime due to a shared method for faster test execution but in the day but the success case should be fast but worst case it should not fail - we'd much rather it occasionally take a second than fail the test suite and add noise to the process.

[NickCraver]

@mgravell I'm tinkering here, but check out https://github.com/StackExchange/StackExchange.Redis/runs/46946456491#r0s34

Note the error from IllegalCombinations presented in BasicTranWithHashExistsCondition - they do not share a multiplexer, but would share a socket worker pool...

StackExchange.Redis.Tests.SortedSetWhenTest ► SortedSetWhenTest.IllegalCombinations (RESP2)

Failed test found in:
  test-results/_pkrvmpptgkbjq6m_2025-07-29_13_12_06.trx
Error:
  Assert.Throws() Failure: No exception was thrown
  Expected: typeof(StackExchange.Redis.RedisServerException)

StackExchange.Redis.Tests.TransactionTests ► TransactionTests.BasicTranWithHashExistsCondition(demandKeyExists: False, keyExists: True, expectTranResult: False) (RESP2)

Failed test found in:
  test-results/_pkrvmpptgkbjq6m_2025-07-29_13_12_06.trx
Error:
  StackExchange.Redis.RedisServerException : ERR GT, LT, and/or NX options at the same time are not compatible

[NickCraver]

@mgravell Did you see comment above?

[mgravell]

The impossible mismatched results? Yes, which inspired me to do some more work on ripping out the IO core. Something is seriously borked.