SF: Fix pacesetter promotion for folded mirroring

The pacesetter display is demoted/promoted in response to a hotplug. On
foldables, the promoted display was hard-coded to the inner display, so
a hotplug while folded would incorrectly use that powered-off display as
the pacesetter, causing system-wide jank until the next fold/unfold.

Fixes: 347248313
Flag: EXEMPT bugfix
Test: Connect and disconnect external display while folded.
Test: Fold and unfold while external display is connected.
Test: Pacesetter is still correct on folded/unfolded boot.
Change-Id: Id5cb29c3cbaa8ed455a15d8be3a32e79a470cce5
diff --git a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
index 007383b..4197cbd 100644
--- a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
+++ b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
@@ -1118,8 +1118,8 @@
                 if (mFlinger.scheduler() && mSchedulerRegistration) {
                     mFlinger.scheduler()->registerDisplay(*physicalId,
                                                           mCreationArgs.refreshRateSelector,
-                                                          std::move(controller),
-                                                          std::move(tracker));
+                                                          std::move(controller), std::move(tracker),
+                                                          mFlinger.mutableActiveDisplayId());
                 }
             }