Make inprocesstests run with root.

This fixes these tests, which after ag/16987854 must run with root
to bypass the signature check and allow them to instrument the
system server.

Bug: 221821427
Test: atest FrameworksInProcessTests
Change-Id: Ic68d85f8a508861ff5a0e26a4703e7fa125f880a
diff --git a/services/tests/inprocesstests/AndroidTest.xml b/services/tests/inprocesstests/AndroidTest.xml
index b541512..f5fea1b 100644
--- a/services/tests/inprocesstests/AndroidTest.xml
+++ b/services/tests/inprocesstests/AndroidTest.xml
@@ -18,6 +18,8 @@
     <option name="test-suite-tag" value="apct" />
     <option name="test-suite-tag" value="apct-instrumentation" />
 
+    <target_preparer class="com.android.tradefed.targetprep.RootTargetPreparer"/>
+
     <target_preparer class="com.android.tradefed.targetprep.suite.SuiteApkInstaller">
         <option name="cleanup-apks" value="true"/>
         <option name="test-file-name" value="FrameworksInProcessTests.apk"/>