MDEV-13013 InnoDB unnecessarily extends data files

- While creating a new InnoDB segment, allocates the extent
before allocating the inode or page allocation even though
the pages are present in fragment segment. This patch does
reserve the extent when InnoDB ran out of fragment pages
in the tablespace.

mysql-test/suite/mariabackup/log_page_corruption.result

@@ -30,13 +30,13 @@ FOUND 1 /Database page corruption detected.*/ in backup.log
 FOUND 1 /completed OK!/ in backup.log
 --- "innodb_corrupted_pages" file content: ---
 test/t1_corrupted
-6 8 9
+4 6 7
 test/t2_corrupted
-7 8 10
+5 6 8
 test/t4_corrupted_new
 1
 test/t5_corrupted_to_rename_renamed
-6
+4
 test/t7_corrupted_to_alter
 3
 ------
@@ -46,19 +46,19 @@ INSERT INTO t3_inc VALUES (3), (4), (5), (6), (7), (8), (9);
 # Backup must not fail, but "innodb_corrupted_pages" file must be created due to --log-innodb-page-corruption option
 --- "innodb_corrupted_pages" file content: ---
 test/t1_corrupted
-6 8 9
+4 6 7
 test/t1_inc_corrupted
-6 8 9
+4 6 7
 test/t2_corrupted
-7 8 10
+5 6 8
 test/t2_inc_corrupted
-7 8 10
+5 6 8
 test/t4_inc_corrupted_new
 1
 test/t5_corrupted_to_rename_renamed
-6
+4
 test/t5_inc_corrupted_to_rename_renamed
-6
+4
 test/t7_inc_corrupted_to_alter
 3
 ------
@@ -82,15 +82,15 @@ DROP TABLE t7_inc_corrupted_to_alter;
 # Full backup with --log-innodb-page-corruption
 --- "innodb_corrupted_pages" file content: ---
 test/t3
-6 8
+4 6
 ------
 # Extend some tablespace and corrupt extended pages for incremental backup
 # Incremental backup --log-innodb-page-corruption
 --- "innodb_corrupted_pages" file content: ---
 test/t3
-6 8
+4 6
 test/t3_inc
-6 8
+4 6
 ------
 # Full backup prepare
 # "innodb_corrupted_pages" file must not exist after successful prepare