Fix missing the implementation of Computer#dump() in ComputerLocked

It's necessary to implement the Computer#dump() in ComputerLocked
to ensure a lock is held when the snapshot feature is disabled.

Bug: 186505771
Test: adb bugreport
Change-Id: I9d3d371320c8e9a550a93177045a5f0ccbb32ffe

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

@@ -4893,6 +4893,11 @@ public class PackageManagerService extends IPackageManager.Stub
                 return super.filterAppAccess(packageName, callingUid, userId);
             }
         }
+        public void dump(int type, FileDescriptor fd, PrintWriter pw, DumpState dumpState) {
+            synchronized (mLock) {
+                super.dump(type, fd, pw, dumpState);
+            }
+        }
     }