fixes #6856 - API v2 - more efficient import puppetclasses for single environment

That's right, so that's the point of putting stubs in a context between this test and the following. This test will get stubs for env2 and it will only import env1. The test is not meaningless as it is though, because without the fix, ```ProxyAPI::Puppet.classes('env2')``` would get called and make the test fail.