Fixes error when creating the db for Query Execution perf tests.

Fix for #994.

This makes the process a bit slower since it calls SaveChanges more often, but it works well.

Additionally fixing kproj and project.json files for the perf tests to reflect they are console apps and not libraries.

@lukewaters 
Because the entire batch is larger than EF supports. I was getting an error indicating that our command was over the limit per single query. This is probably a Sql Server limitation.