Run appsFilter.systemReady() last

This change moves the appsFilter systemReady call to the end of the PMS
systemReady method to avoid it acquiring the package lock on a
background thread as the lock is required by several other blocks in the
method.

Before: MakePackageMangerServiceReady timing was 300-500ms, most of that
time spent setting up preferred activities as it waited for mLock to
become available
After: MakePackageManagerSerivceReady timing is ~130ms.

Test: atest AppEnumerationTests
Fixes: 162347084
Fixes: 163613646
Change-Id: Iac2948fb2ad66e45161627f637f039a5f4faf88c

services/core/java/com/android/server/pm/PackageManagerService.java

@@ -21558,8 +21558,6 @@ public class PackageManagerService extends IPackageManager.Stub
                         .getUriFor(Secure.INSTANT_APPS_ENABLED), false, co, UserHandle.USER_ALL);
         co.onChange(true);
 
-        mAppsFilter.onSystemReady();
-
         // Disable any carrier apps. We do this very early in boot to prevent the apps from being
         // disabled after already being started.
         CarrierAppUtils.disableCarrierAppsUntilPrivileged(
@@ -21708,6 +21706,9 @@ public class PackageManagerService extends IPackageManager.Stub
         mInstallerService.restoreAndApplyStagedSessionIfNeeded();
 
         mExistingPackages = null;
+
+        // We'll do this last as it builds its cache while holding mLock via callback.
+        mAppsFilter.onSystemReady();
     }
 
     public void waitForAppDataPrepared() {