SF: Rewrite test for leader display designation

Bug: 259436835
Fixes: 262417075
Test: MultiDisplayLeaderTest.foldable
Change-Id: Icfe2bf1dedcfbdd09f98caf6db24c6b121afbf1c
diff --git a/services/surfaceflinger/tests/unittests/Android.bp b/services/surfaceflinger/tests/unittests/Android.bp
index 87c3c65..a5b508a 100644
--- a/services/surfaceflinger/tests/unittests/Android.bp
+++ b/services/surfaceflinger/tests/unittests/Android.bp
@@ -105,6 +105,7 @@
         "SurfaceFlinger_DisplayTransactionCommitTest.cpp",
         "SurfaceFlinger_GetDisplayNativePrimariesTest.cpp",
         "SurfaceFlinger_HotplugTest.cpp",
+        "SurfaceFlinger_MultiDisplayLeaderTest.cpp",
         "SurfaceFlinger_NotifyPowerBoostTest.cpp",
         "SurfaceFlinger_OnInitializeDisplaysTest.cpp",
         "SurfaceFlinger_PowerHintTest.cpp",