Throw on version mismatch

[LilithHafner]

If RegressionTests is running on a different version in the controlling process and the sub-process, throw. Theoretically, we could have separate packages and complex, permissive compat between them, but exact version equality is certainly better now, and probably better for the foreseeable future.

I suspect that this is the underlying issue causing #47 and causing AliasTables to continue to see evals tracked even though test reports using RegressionTests 0.0.8. bench/Manifest is checked in in that package.