Make test report and error buffers connection specific

[hugoduncan]

When working with multiple repls, the test report and error buffers are shared. This leads to

• the buffers often having the wrong directory associated with them
• test reports from one repl no longer linking to source properly whan a test i started in another repl
• test reports from one repl being lost when tests in another repl complete

Making these buffers connection specific would solve these issue.