large_scale_long_lived and large_scale_model genny workloads potentially faulty

While working on PM-1986 Alex Cameron wrote a new workload based on large_scale_long_lived and large_scale_model workloads. I was testing if the workload distributes reads/writes binomially across the _id keyspace and found reads and writes actually do not end up going to WiredTiger.

The filters we use on _id for reads and updates assume _id to be numeric, whereas the load phase lets _id to be defaulted to it's ObjectID representation. We created WT-7041 to fix this bug in the new workload.

Having based new workload on large_scale_long_lived and large_scale_model, it is very likely that these workloads are not doing the right thing at all, and doing reads/writes with filters that do not match any documents.

This ticket is to check if the workloads have been faulty and if yes, fix them. WT-7041 could hint at the possible solution.