Remove debug.test file

First, thanks for developing such awesome atom package. 

I am using this for past couple of days. One thing I came across is that temp file generated `debug.test` does not get automatically deleted after I stop the debugging. Is this supposed to work like this?

I am on:
* Mac OSX 10.13.3 
* Atom 1.25.0 x64
* go-debug 1.6.0