audio: Use 'join' instead of 'stop' for stream workers

Calling 'stop' can cause the worker thread to terminate
before it handles the 'halReservedExit' command. This should
be avoided because a proper exit sequence may do cleanups.
Since all stream workers must handle the 'halReservedExit'
command, use of 'stop' should not be needed (if the thread
code gets stuck on a call to drivers, calling 'stop' will
not interrupt this), thus it is being replaced by 'join'.

Bug: 344482249
Test: atest CtsMediaAudioTestCases
Test: atest VtsHalAudioCoreTargetTest
Change-Id: If13f7239423657b80091239ff67e7fe350957e2e

audio/aidl/default/Stream.cpp

@@ -772,7 +772,7 @@ ndk::ScopedAStatus StreamCommonImpl::close() {
     if (!isClosed()) {
         stopWorker();
         LOG(DEBUG) << __func__ << ": joining the worker thread...";
-        mWorker->stop();
+        mWorker->join();
         LOG(DEBUG) << __func__ << ": worker thread joined";
         onClose(mWorker->setClosed());
         return ndk::ScopedAStatus::ok();

audio/aidl/default/include/core-impl/Stream.h

@@ -245,7 +245,7 @@ struct StreamWorkerInterface {
     virtual StreamDescriptor::State setClosed() = 0;
     virtual bool start() = 0;
     virtual pid_t getTid() = 0;
-    virtual void stop() = 0;
+    virtual void join() = 0;
     virtual std::string getError() = 0;
 };
 
@@ -265,7 +265,7 @@ class StreamWorkerImpl : public StreamWorkerInterface,
         return WorkerImpl::start(WorkerImpl::kThreadName, ANDROID_PRIORITY_URGENT_AUDIO);
     }
     pid_t getTid() override { return WorkerImpl::getTid(); }
-    void stop() override { return WorkerImpl::stop(); }
+    void join() override { return WorkerImpl::join(); }
     std::string getError() override { return WorkerImpl::getError(); }
 };