Fix for one of the problems in bug 3323. Once the heap cache was full, it was never used anymore.  When we want to find a cache file for use, it only matters whether there are any in the cache, not whether the cache is full.
Fix for one of the problems in bug 3323.
Once the heap cache was full, it was never used anymore.  When we want
to find a cache file for use, it only matters whether there are any in
the cache, not whether the cache is full.

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