Revert "innodb: Add thd_wait_begin/end for Sync IO"

Summary:
This reverts commit 721fbd6.

The stall mentioned in the commit above already has DISKIO wait begin/end in `buf_read_page_low`. So this extra DISKIO wait is not needed for that. However, this API is also used to write to the log on the commit code path while the binlog mutex is held, which causes lots of commit stalls.

Differential Revision: D56561026

fbshipit-source-id: 868bc18

Author: george-reynya

storage/innobase/os/os0file.cc

@@ -87,7 +87,6 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
 #include "my_rnd.h"
 #include "mysql/service_mysql_keyring.h"
 #include "mysqld.h"
-#include "mysys/mysys_priv.h"
 
 #include <sys/types.h>
 #include <zlib.h>
@@ -2047,7 +2046,6 @@ static file::Block *os_file_encrypt_log(const IORequest &type, void *&buf,
 @return the number of bytes read/written or negative value on error */
 ssize_t SyncFileIO::execute(const IORequest &request) {
   ssize_t n_bytes;
-  My_thd_wait_scope wait(THD_WAIT_DISKIO);
 
   if (request.is_read()) {
     n_bytes = pread(m_fh, m_buf, m_n, m_offset);