Break the circular dependency between iocore and tscore.

[jpeach]

The re-introduction of the MTHashTable class created a dependency from tscore to iocore, since it uses proxy mutexes, which are tightly coupled to the event system. We can break this circular dependency by moving the class into the QUIC library as an implementation detail, since that already depends on the event system

This fixes #9768.

[jpeach]

     Setting up : Copying '/home/jenkins/workspace/Github_Builds/autest/src/tests/gold_tests/pluginTest/polite_hook_wait/.libs/polite_hook_wait.so' to '/tmp/sandbox/polite_hook_wait/ts/plugin' - Passed
     Test : Checking that ReturnCode == 0 - Failed
        Reason: Returned Value -9 != 0
     Time-Out : Process finishes within expected time - Passed
        Reason: Returned value: 10.503296613693237 < 600.0

Seems like a CI problem?

[jpeach]

Wait, the copy isn't the error, I guess it's a return code check from this somewhere?

tr = Test.AddTestRun()
tr.Processes.Default.StartBefore(server)
tr.Processes.Default.StartBefore(ts)
tr.Processes.Default.Command = (
    'curl --verbose --ipv4 --header "Host:myhost.test" http://localhost:{}/ 2>curl.txt'.format(ts.Variables.port)
)
tr.Processes.Default.ReturnCode = 0

tr = Test.AddTestRun()
tr.Processes.Default.Command = (
    'curl --verbose --ipv4 --header "Host:myhost.test" http://localhost:{}/ 2>curl.txt'.format(ts.Variables.port)
)
tr.Processes.Default.ReturnCode = 0

tr = Test.AddTestRun()
tr.Processes.Default.Command = "grep -F HTTP/ curl.txt"
tr.Processes.Default.Streams.stdout = "curl.gold"
tr.Processes.Default.ReturnCode = 0

But it's not clear which one fails or why. Exit code 9 from curl is " FTP access denied", so maybe it's the grep that fails? If there's an expected output file, I wonder why the test runs grep manually?

[jpeach]

[approve ci autest]

[cmcfarlen]

fantastic!