multi-emit fsi debug -- watch variables don't work

[KevinRansom]

In this session there are four sperate submissions, all sent in one go by using Alt+A select all then Debug in Fsi from the context menu. Note that locals and Autos are empty .. and the watch window claims x, y and z do not exist.

This happens because each section of code is separated by ;; and executed in a single submission.

Expected: All submitted code to be compiled and then executed.

Note: This behavior requires this PR: https://github.com/dotnet/fsharp/pull/14537