Call stopControllerFactory atexit in the Darwin framework.

We have lots of things with static destructors that assert clean
shutdown in the destructor.  That means that calling exit() without a
clean shutdown is pretty much guaranteed to lead to a shutdown crash.

Just ensure that we are in fact shutting down the
MTRDeviceControllerFactory if exit() is called, to avoid those crashes.

Fixes project-chip#14859

src/darwin/Framework/CHIP/MTRDeviceControllerFactory.mm

@@ -44,6 +44,8 @@
 #include <lib/support/TestPersistentStorageDelegate.h>
 #include <platform/PlatformManager.h>
 
+#include <cstdlib>
+
 using namespace chip;
 using namespace chip::Controller;
 
@@ -58,6 +60,9 @@
 static NSString * const kErrorCDCertStoreInit = @"Init failure while initializing Certificate Declaration Signing Keys store";
 static NSString * const kErrorOtaProviderInit = @"Init failure while creating an OTA provider delegate";
 
+static bool sExitHandlerRegistered = false;
+static void ShutdownOnExit() { [[MTRDeviceControllerFactory sharedInstance] stopControllerFactory]; }
+
 @interface MTRDeviceControllerFactory ()
 
 @property (atomic, readonly) dispatch_queue_t chipWorkQueue;
@@ -382,7 +387,14 @@ - (BOOL)startControllerFactory:(MTRDeviceControllerFactoryParams *)startupParams
         // This needs to happen after DeviceControllerFactory::Init,
         // because that creates (lazily, by calling functions with
         // static variables in them) some static-lifetime objects.
-        chip::HeapObjectPoolExitHandling::IgnoreLeaksOnExit();
+        if (!sExitHandlerRegistered) {
+            int ret = atexit(ShutdownOnExit);
+            if (ret != 0) {
+                MTR_LOG_ERROR("Error registering exit handler: %d", ret);
+                return;
+            }
+        }
+        HeapObjectPoolExitHandling::IgnoreLeaksOnExit();
 
         // Make sure we don't leave a system state running while we have no
         // controllers started.  This is working around the fact that a system