fre make create-dockerfile test

[singhd789]

Is your feature request related to a problem? Please describe.
fre make create-dockerfile needs an associated test.

Describe the solution you'd like
Tests could include:

• existence of model yaml, platform yaml, and compile yaml
• existence of checkout script, makefile, linkline script in tmp location (going to be copied into container via dockerfile)
• correct checkout script (?) - cannot be run in parallel with container build
• successful dockerfile creation (look for things it should include - like copying checkout script, makefile, and linkline)
• successful container build (if --execute is used)
• other failures...