Have recreateTaskbar perform recreate on UiThread.

Test: Taskbar{AllApps,Overlay}ControllerTest
Bug: 230027385
Flag: TEST_ONLY
Change-Id: I663e5ad7bb37e73381e2ef9d787c80177cfdf7a7

quickstep/tests/multivalentTests/src/com/android/launcher3/taskbar/allapps/TaskbarAllAppsControllerTest.kt

@@ -65,9 +65,8 @@ class TaskbarAllAppsControllerTest {
     }
 
     @Test
-    @UiThreadTest
     fun testToggle_taskbarRecreated_allAppsReopened() {
-        allAppsController.toggle()
+        getInstrumentation().runOnMainSync { allAppsController.toggle() }
         taskbarUnitTestRule.recreateTaskbar()
         assertThat(allAppsController.isOpen).isTrue()
     }

quickstep/tests/multivalentTests/src/com/android/launcher3/taskbar/overlay/TaskbarOverlayControllerTest.kt

@@ -150,9 +150,10 @@ class TaskbarOverlayControllerTest {
     }
 
     @Test
-    @UiThreadTest
     fun testRecreateTaskbar_closesWindow() {
-        TestOverlayView.show(overlayController.requestWindow())
+        getInstrumentation().runOnMainSync {
+            TestOverlayView.show(overlayController.requestWindow())
+        }
         taskbarUnitTestRule.recreateTaskbar()
         assertThat(hasOpenView(taskbarContext, TYPE_TASKBAR_OVERLAY_PROXY)).isFalse()
     }

quickstep/tests/multivalentTests/src/com/android/launcher3/taskbar/rules/TaskbarUnitTestRule.kt

@@ -135,7 +135,7 @@ class TaskbarUnitTestRule(private val testInstance: Any, private val context: Co
 
     /** Simulates Taskbar recreation lifecycle. */
     fun recreateTaskbar() {
-        taskbarManager.recreateTaskbar()
+        instrumentation.runOnMainSync { taskbarManager.recreateTaskbar() }
         injectControllers()
     }