increase BenchmarkBigIT size (#5609)
increase BenchmarkBigIT size (#5609)

## What is the goal of this PR?
To increase the size of the `BenchmarkBigIT` test so that it doesn't timeout randomly.

## What are the changes implemented in this PR?
Increased `BenchmarkBigIT` size.

lolski/grakn,graknlabs/grakn,graknlabs/grakn,graknlabs/grakn,lolski/grakn,graknlabs/grakn,lolski/grakn,lolski/grakn