Adds caller check to getAllPackages()

This change enforces that only system, root or shell may call
getAllPackages(), a hidden API that shares all package names regardless
of user, instant app or package visibility rules.

Bug: 174661955
Change-Id: I77460ae19a4d41151577646441f11e2eddbb741a
Merged-In: I77460ae19a4d41151577646441f11e2eddbb741a
(cherry picked from commit 8124efd57b)

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

@@ -6334,6 +6334,7 @@ public class PackageManagerService extends IPackageManager.Stub
 
     @Override
     public List<String> getAllPackages() {
+        enforceSystemOrRootOrShell("getAllPackages is limited to privileged callers");
         final int callingUid = Binder.getCallingUid();
         final int callingUserId = UserHandle.getUserId(callingUid);
         synchronized (mPackages) {