MDEV-26740 Inplace alter rebuild increases file size

PageBulk::init(): Unnecessary reserves the extent before
allocating a page for bulk insert. btr_page_alloc()
capable of handing the extending of tablespace.

mysql-test/suite/innodb_zip/r/innochecksum_3.result

@@ -173,7 +173,6 @@ Filename::tab#.ibd
 #::#		|		Index page			|	index id=#, page level=#, No. of records=#, garbage=#, -
 #::#		|		Index page			|	index id=#, page level=#, No. of records=#, garbage=#, -
 #::#		|		Index page			|	index id=#, page level=#, No. of records=#, garbage=#, -
-#::#		|		Freshly allocated page		|	-
 # Variables used by page type dump for ibdata1
 
 Variables (--variable-name=value)
@@ -208,7 +207,6 @@ Filename::tab#.ibd
 #::#		|		Index page			|	index id=#, page level=#, No. of records=#, garbage=#, -
 #::#		|		Index page			|	index id=#, page level=#, No. of records=#, garbage=#, -
 #::#		|		Index page			|	index id=#, page level=#, No. of records=#, garbage=#, -
-#::#		|		Freshly allocated page		|	-
 [6]: check the valid lower bound values for option
 # allow-mismatches,page,start-page,end-page
 [9]: check the both short and long options "page" and "start-page" when

storage/innobase/btr/btr0bulk.cc

@@ -70,24 +70,15 @@ PageBulk::init()
 		alloc_mtr.start();
 		m_index->set_modified(alloc_mtr);
 
-		ulint	n_reserved;
-		bool	success;
-		success = fsp_reserve_free_extents(&n_reserved,
-						   m_index->table->space,
-						   1, FSP_NORMAL, &alloc_mtr);
-		if (!success) {
-			alloc_mtr.commit();
-			m_mtr.commit();
-			return(DB_OUT_OF_FILE_SPACE);
-		}
-
 		/* Allocate a new page. */
 		new_block = btr_page_alloc(m_index, 0, FSP_UP, m_level,
 					   &alloc_mtr, &m_mtr);
 
-		m_index->table->space->release_free_extents(n_reserved);
-
 		alloc_mtr.commit();
+		if (!new_block) {
+			m_mtr.commit();
+			return DB_OUT_OF_FILE_SPACE;
+		}
 
 		new_page = buf_block_get_frame(new_block);
 		new_page_zip = buf_block_get_page_zip(new_block);