Bug: You can see here that the two programs under tests/ are equivalent, just one uses
pipelines and one always assigns to a new sketchgroup. However, the pipeline
produces weird visual bugs. Jess did a git bisect to figure out this was the problem that
Mike was experiencing, around weird visual artifacts with filleting.
Ultimately the bug was that my rewritten `execute_pipe_body` function was executing
the first expression of the pipeline body twice! In most unit tests this didn't matter,
because the first expression in a pipeline was startSketchAt. No big deal to run that
twice. However, in Mike's program, the first expression was `make_circle` or `pentagon`,
user-defined functions that sent a lot of API calls. This meant the pipeline duplicated a lot
of geometry, causing Z-fighting and weird artifacts.
15ebbe6947
