Fix shortcut backup CTS

There's a version of GMS-core that changes the current transport upon
BOOT_COMPLETED, so we need to select local transport explicitly.

Bug: 64203677
Test: cts-tradefed run cts-dev --skip-device-info --skip-preconditions --skip-system-status-check com.android.compatibility.common.tradefed.targetprep.NetworkConnectivityChecker -a armeabi-v7a -l INFO -m CtsShortcutHostTestCases
Change-Id: I7f8ef684864179d3c1ee3459559cff7c91e7d091
diff --git a/hostsidetests/shortcuts/hostside/src/android/content/pm/cts/shortcuthost/ShortcutManagerBackupTest.java b/hostsidetests/shortcuts/hostside/src/android/content/pm/cts/shortcuthost/ShortcutManagerBackupTest.java
index 7859784..960b41f 100644
--- a/hostsidetests/shortcuts/hostside/src/android/content/pm/cts/shortcuthost/ShortcutManagerBackupTest.java
+++ b/hostsidetests/shortcuts/hostside/src/android/content/pm/cts/shortcuthost/ShortcutManagerBackupTest.java
@@ -93,15 +93,18 @@
         super.tearDown();
     }
 
-    private void doBackup() throws DeviceNotAvailableException {
+    private void doBackup() throws Exception {
         CLog.i("Backing up package android...");
 
-        executeShellCommandWithLog("dumpsys backup");
+        waitUntilBroadcastsDrain(); // b/64203677
 
+        CLog.i("Making sure the local transport is selected...");
         assertContainsRegex(
-                "LocalTransport must be selected.",
-                "\\*.*LocalTransport",
-                executeShellCommandWithLog("bmgr list transports"));
+                "^Selected transport android/com.android.internal.backup.LocalTransport",
+                executeShellCommandWithLog(
+                        "bmgr transport android/com.android.internal.backup.LocalTransport"));
+
+        executeShellCommandWithLog("dumpsys backup");
 
         assertContainsRegex(
                 "Wiped",