MDEV-34929 page-compressed tables do not work on Windows

Remove workaround for MDEV-13941, it served for 5 years,and all affected
pre-release 10.2 installation should have been already fixed in between.

Apparently Innodb is using is_sparse parameter in os_file_set_size()
inconsistently, and it passes is_sparse=false now during first file
extension. With MDEV-13941 workaround in place, it would unsparse
the file, which is makes compression not to work at all anymore.

mysql-test/suite/innodb/r/page_compression_windows.result

@@ -0,0 +1,6 @@
+create table t_compressed(b longblob) engine=InnoDB page_compressed=1;
+insert into  t_compressed values(repeat(1,1000000));
+select allocated_size < file_size from information_schema.innodb_sys_tablespaces where name='test/t_compressed';
+allocated_size < file_size
+1
+drop table t_compressed;

mysql-test/suite/innodb/t/page_compression_windows.opt

@@ -0,0 +1 @@
+--innodb-sys-tablespaces

mysql-test/suite/innodb/t/page_compression_windows.test

@@ -0,0 +1,7 @@
+--source include/have_innodb.inc
+--source include/windows.inc
+create table t_compressed(b longblob) engine=InnoDB page_compressed=1;
+insert into  t_compressed values(repeat(1,1000000));
+# Check that compression worked, i.e allocated size (physical file size) < logical file size
+select allocated_size < file_size from information_schema.innodb_sys_tablespaces where name='test/t_compressed';
+drop table t_compressed;

storage/innobase/os/os0file.cc

@@ -3210,22 +3210,8 @@ os_file_set_size(
 
 #ifdef _WIN32
 	/* On Windows, changing file size works well and as expected for both
-	sparse and normal files.
-
-	However, 10.2 up until 10.2.9 made every file sparse in innodb,
-	causing NTFS fragmentation issues(MDEV-13941). We try to undo
-	the damage, and unsparse the file.*/
-
-	if (!is_sparse && os_is_sparse_file_supported(file)) {
-		if (!os_file_set_sparse_win32(file, false))
-			/* Unsparsing file failed. Fallback to writing binary
-			zeros, to avoid even higher fragmentation.*/
-			goto fallback;
-	}
-
+	sparse and normal files. */
 	return os_file_change_size_win32(name, file, size);
-
-fallback:
 #else
 	struct stat statbuf;