Add a way to preserve information between VS Code extension and running test

[davidmedinasigasi]

I'm trying to test a VS Code extension and I came across an issue when using a register between the extension and the test.

The problem: The extension sets some values into a register that the tests consume, when running the test using the launch configuration everything works, but when using the test explorer they failed.

I've attached a minimal project that reproduces this issue.

helloworld-test-sample.zip