[Mondrian] Performance: CellInfoPool

[Anton Nikitin]

Hi All.

It seems to me that CellInfoPool is too much slow on huge queries.

I use customized Mondrian version based on 2.3.2

When running a query which results in 300000 cells I'm observing that
CellInfoPool implementation is 10 times slower than CellInfoMap.

In my case I simply turned off CellInfoPool in all case (memory is less
significant for us than performance). 

Anton