optimize deleteAllIndexes tests

Author: cherylEnkidu

firebase-firestore/src/test/java/com/google/firebase/firestore/local/SQLiteLocalStoreTest.java

@@ -628,8 +628,6 @@ public void testDeleteAllIndexesWorksWithIndexAutoCreation() {
     assertRemoteDocumentsRead(/* byKey= */ 0, /* byCollection= */ 2);
     assertQueryReturned("coll/a", "coll/e");
 
-    setIndexAutoCreationEnabled(false);
-
     backfillIndexes();
 
     executeQuery(query);
@@ -641,6 +639,13 @@ public void testDeleteAllIndexesWorksWithIndexAutoCreation() {
     executeQuery(query);
     assertRemoteDocumentsRead(/* byKey= */ 0, /* byCollection= */ 2);
     assertQueryReturned("coll/a", "coll/e");
+
+    // Field index is created again.
+    backfillIndexes();
+
+    executeQuery(query);
+    assertRemoteDocumentsRead(/* byKey= */ 2, /* byCollection= */ 0);
+    assertQueryReturned("coll/a", "coll/e");
   }
 
   @Test