Create a low level test suite

[raix]

It might be a good idea to actually test the perl5db IO directly. We might be able to use jest snapshots for the ease of it.

The reason for doing this test suite is to:

• verify in detail what the IO of the debugger is on different systems. We might have to add an abstraction layer to smooth out lacking features and inconsistencies.
• make it easier for the community users to run the test suite on their system.

An idea could be to use the vs code extensions error reporting tool - we might even be able to run the test suite on new installations, making sure the system is compliant - if not the report to the user and vs code thing. (need to investigate further)

We could also publish the test suite on npm - then if users encounter issues they can run the test suite and paste in the result in a github issue?

[hoehrmann]

The newly added debugRaw option should go a long way towards this, it logs the I/O with the debugger in a vscode output channel, making it easy for users to copy and paste it into issue reports (as well as helping developers immensely).