Fixed command not found error during tests on windows

Added missing cmdSuffix in tests. Previously it was used only in the actual code. This fixes quite a number of tests on Windows.
For the gofmt part, you are right, it usually happens automatically when I save the file but here I just used sed to replace everything at once. Will fix.

There are no details regarding the Windows world. It is simply a matter of appending .exe to every command. Of course there are many ways that we could do this. I merely followed what's done in server and appended cmdSuffix everywhere. This way, if we ever need any other extension we only need to change cmdSuffix and it should work. I can hide it under another layer of abstraction if needed though, but imo this should suffice.