Enforce permission checks in getting app exit reasons

Bug: 165595677
Test: atest CtsSecurityTestCases:ActivityManagerTest
Change-Id: Ia758d32bce6b2ac4c7145a96eccf68a962f0748b
(cherry picked from commit e9b1dd415fed5415bc21abbd8e2f653fda5cf30c)

services/core/java/com/android/server/am/ActivityManagerService.java

diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index 3b85180..091c77e 100644
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -10459,12 +10459,10 @@
         } finally {
             Binder.restoreCallingIdentity(identity);
         }
-        if (uid == Process.INVALID_UID) {
-            return Process.INVALID_UID;
-        }
+        // If the uid is Process.INVALID_UID, the below 'if' check will be always true
         if (UserHandle.getAppId(uid) != UserHandle.getAppId(callingUid)) {
             // Requires the DUMP permission if the target package doesn't belong
-            // to the caller.
+            // to the caller or it doesn't exist.
             enforceCallingPermission(android.Manifest.permission.DUMP, function);
         }
         return uid;