Backported multi_update_check_table_access() from 5.6

The code is slightly different in MariaDB, becasue we instansiate fields in merged tables earlier.

mysql-test/mysql-test-run.pl:
  Fixed comment
mysql-test/r/view_grant.result:
  Merged test case from 5.6
mysql-test/t/view_grant.test:
  Merged test case from 5.6
sql/sql_parse.cc:
  Reset orig_want_privilege as this will be rechecked later.
  If not, we will have a problem in mysql_multi_update_prepare() for the call to mysql_handle_derived()
sql/sql_update.cc:
  Backport multi_update_check_table_access() from 5.6