Most things where wrong in the test suite.
The one thing that was a bug was that table_map_id was in some places
defined as ulong and in other places as ulonglong. On Linux 64 bit this
is not a problem as ulong == ulonglong, but on windows this caused failures.
Fixed by ensuring that all instances of table_map_id are ulonglong.
this test loads sql_errlog plugin. then in a second connection
it triggers an error, this locks the plugin in that thd.
then the plugin is uninstalled in the default connection.
but that doesn't unload the plugin, as it's still locked. it'll
auto-unload after the foo connection is closed. without an explicit
disconnect it is closed after mysqltest exits and the post-test check
might still see sql_errlog not fully unoaded.