Fix all runtime permissions being considered changing protection from

non-runtime on first boot.

1. Don't check against a newly created permission object, as it will
always have signature protection and be considered non-runtime.

2. "Placeholder" permissions of TYPE_CONFIG shouldn't count as an
existing permission, as they are only used for assigning GIDs.

Bug: 183304624
Test: manual
Test: atest PermissionEscalationTest (from ag/12980961)
Change-Id: I39055a914a8575c754a3a4def2b2a31071605986

services/core/java/com/android/server/pm/permission/Permission.java

@@ -435,11 +435,12 @@ public final class Permission {
                 }
             }
         }
+        boolean wasNonRuntime = permission != null && permission.mType != TYPE_CONFIG
+                && !permission.isRuntime();
         if (permission == null) {
             permission = new Permission(permissionInfo.name, permissionInfo.packageName,
                     TYPE_MANIFEST);
         }
-        boolean wasNonRuntime = !permission.isRuntime();
         StringBuilder r = null;
         if (!permission.mReconciled) {
             if (permission.mPermissionInfo.packageName == null