Summary
Currently, we have checks that make sure we can divide the number of collections per the number of threads so each thread can work on the same number of collections. These checks look like this:

testutil_assert(collection_count % tc->thread_count == 0); 

They are present in the insert_operation (default and user-defined in some tests) as well as in the default populate function. There might be more when this ticket is taken.

It is too restrictive, we could associate more or less collection to a thread without failing.

Motivation

• Is this issue urgent?
  Nothing urgent, just convenient.

Acceptance Criteria (Definition of Done)

• Testing
  We need to be able to define any number of threads in the configuration file. We could get a warning if not all threads are used.
• Documentation update
  Check the documentation written as part of WT-9109 and WT-9111