Revert "Use instrumentation arg to prevent unnecessary delays in unit tests"

This reverts commit b5d08b246e875efdb3d8405501f481a6cc12b9f6.

Reason for revert: A similar G3 CL was reverted: cl/582384131

Change-Id: If3e3d6f1aacd297ef357d6330ca3e98e857ea71d
diff --git a/tests/Launcher3Tests.xml b/tests/Launcher3Tests.xml
index 0aed1e1..3fff622 100644
--- a/tests/Launcher3Tests.xml
+++ b/tests/Launcher3Tests.xml
@@ -46,6 +46,5 @@
     <test class="com.android.tradefed.testtype.AndroidJUnitTest" >
         <option name="package" value="com.android.launcher3.tests" />
         <option name="runner" value="androidx.test.runner.AndroidJUnitRunner" />
-        <option name="instrumentation-arg" key="waitForActivitiesToComplete" value="false" />
     </test>
 </configuration>