Protect GDK_mallocedbytes_estimate by its own lock to avoid deadlock.
Protect GDK_mallocedbytes_estimate by its own lock to avoid deadlock.

zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb