Firestore: Fix comment in testDoesNotAutoCreateIndexesWhenIndexLookUpIsExpensive (#5219)

Author: dconeybe

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

@@ -444,9 +444,7 @@ public void testDoesNotAutoCreateIndexesWhenIndexLookUpIsExpensive() {
     applyRemoteEvent(
         addedRemoteEvent(doc("coll/e", 10, map("array", Arrays.asList(2, 0, 8))), targetId));
 
-    // First time query runs without indexes.
-    // Based on current heuristic, collection document counts (5) > 2 * resultSize (2).
-    // Full matched index should be created.
+    // SDK will not create indexes since relative read cost is too large.
     executeQuery(query);
     assertRemoteDocumentsRead(/* byKey= */ 0, /* byCollection= */ 2);
     assertQueryReturned("coll/a", "coll/e");
@@ -479,7 +477,6 @@ public void testIndexAutoCreationWorksWhenBackfillerRunsHalfway() {
     // Based on current heuristic, collection document counts (5) > 2 * resultSize (2).
     // Full matched index should be created.
     executeQuery(query);
-    // Only document a matches the result
     assertRemoteDocumentsRead(/* byKey= */ 0, /* byCollection= */ 2);
     assertQueryReturned("coll/a", "coll/e");