Add template for SwitchUserTargetPreparer

Test: build TF
Bug: 129495356
Change-Id: I576c3295dcdd5794f19df107d10e17b0bf0a5185
diff --git a/res/config/template/preparers/switch-user.xml b/res/config/template/preparers/switch-user.xml
new file mode 100644
index 0000000..22f848c
--- /dev/null
+++ b/res/config/template/preparers/switch-user.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright 2019 Google Inc. All Rights Reserved -->
+<configuration description="A preparer for switching to a different user.">
+    <!-- By default it does not switch. -->
+    <target_preparer class="com.android.tradefed.targetprep.SwitchUserTargetPreparer" />
+</configuration>
\ No newline at end of file