Use page_is_leaf() where applicable.

storage/innobase/btr/btr0btr.cc

@@ -2943,7 +2943,7 @@ btr_page_split_and_insert(
 	btr_page_create(new_block, new_page_zip, cursor->index,
 			btr_page_get_level(page, mtr), mtr);
 	/* Only record the leaf level page splits. */
-	if (btr_page_get_level(page, mtr) == 0) {
+	if (page_is_leaf(page)) {
 		cursor->index->stat_defrag_n_page_split ++;
 		cursor->index->stat_defrag_modified_counter ++;
 		btr_defragment_save_defrag_stats_if_needed(cursor->index);

storage/innobase/btr/btr0cur.cc

@@ -2175,7 +2175,7 @@ btr_cur_open_at_index_side_func(
 		page = buf_block_get_frame(block);
 
 		if (height == ULINT_UNDEFINED
-		    && btr_page_get_level(page, mtr) == 0
+		    && page_is_leaf(page)
 		    && rw_latch != RW_NO_LATCH
 		    && rw_latch != root_leaf_rw_latch) {
 			/* We should retry to get the page, because the root page
@@ -2532,7 +2532,7 @@ btr_cur_open_at_rnd_pos_func(
 		page = buf_block_get_frame(block);
 
 		if (height == ULINT_UNDEFINED
-		    && btr_page_get_level(page, mtr) == 0
+		    && page_is_leaf(page)
 		    && rw_latch != RW_NO_LATCH
 		    && rw_latch != root_leaf_rw_latch) {
 			/* We should retry to get the page, because the root page

storage/innobase/btr/btr0defragment.cc

@@ -233,7 +233,9 @@ btr_defragment_add_index(
 		return NULL;
 	}
 
-	if (btr_page_get_level(page, &mtr) == 0) {
+	ut_ad(page_is_root(page));
+
+	if (page_is_leaf(page)) {
 		// Index root is a leaf page, no need to defragment.
 		mtr_commit(&mtr);
 		return NULL;

storage/innobase/dict/dict0stats.cc

@@ -1553,7 +1553,7 @@ dict_stats_analyze_index_below_cur(
 
 		page = buf_block_get_frame(block);
 
-		if (btr_page_get_level(page, mtr) == 0) {
+		if (page_is_leaf(page)) {
 			/* leaf level */
 			break;
 		}
@@ -1598,7 +1598,7 @@ dict_stats_analyze_index_below_cur(
 	}
 
 	/* make sure we got a leaf page as a result from the above loop */
-	ut_ad(btr_page_get_level(page, &mtr) == 0);
+	ut_ad(page_is_leaf(page));
 
 	/* scan the leaf page and find the number of distinct keys,
 	when looking only at the first n_prefix columns; also estimate