Fix[ntcs_async.cpp]: lost wakeup on execute

[678098]

Description

The real time point annotations t0-t4 show the exact sequence of events that causes a lost wakeup of executor.

Thread 1 (ntcs::Async::State::run):

    while (state->d_runState == k_RUN_STATE_STARTED) {
        bdlb::NullableValue<bsls::TimeInterval> deadline =
            state->d_chronology_sp->earliest();  // t0 - deadline is NULL

        ntccfg::ConditionMutexGuard guard(&state->d_runMutex); // t3 - thread un-sleeps and locks the mutex

        if (deadline.isNull()) {
            state->d_runCondition.wait(&state->d_runMutex); // t4 - thread waits for signal (forever, if there are no more functors enqueued)
        }
        else {
            state->d_runCondition.timedWait(&state->d_runMutex,
                                            deadline.value());
        }

        while (state->d_chronology_sp->hasAnyScheduledOrDeferred()) {
            state->d_chronology_sp->announce(state->d_dynamic);
        }
    }

Thread 2 (ntcs::Chronology::execute):

void Chronology::execute(const ntci::Executor::Functor& functor)
{
    {
        LockGuard lock(&d_mutex);

        bool wasEmpty = d_functorQueue.empty();
        if (wasEmpty) {
            d_functorQueue.reserve(8 * 1024);
        }
        d_functorQueue.push_back(functor);  // t1 - functor is enqueued

        if (wasEmpty) {
            d_functorQueueEmpty = false;
        }
    }

    d_interruptor_sp->interruptAll();  // t2 - mutex is locked and signal is sent
}

Simply, the runner thread might miss a signal from interruptAll.

UT

Causes the following UT failure:

 500/1012 Test  #500: ntc ntcs::AsyncTest::verifyFunction .................................................***Timeout 600.01 sec


99% tests passed, 1 tests failed out of 500

Total Test time (real) = 624.04 sec

The following tests FAILED:
	500 - ntc ntcs::AsyncTest::verifyFunction (Timeout)
Errors while running CTest
FAILED: CMakeFiles/test.util 
cd /workspace/ntf-core/build && /usr/local/bin/ctest --force-new-ctest-process --stop-on-failure --output-on-failure --output-junit Testing/Temporary/Test.xml
ninja: build stopped: subcommand failed.