Simplify Environments in Dataflow Tests

[bjthehun]

Closes #691:

• Helper functions for variable/R function/etc. definitions
• Replace previous definitions in defines
• Also: (optionally named) argumentInCalls for function call vertices
• Simplify environment definitions themselves

[EagleoutIce]

I really like this so far. It would be nice to have another builder-like pattern for the environments as well. Especially to avoid the otherwise required merges to achieve maybes/sets of values.

Thank you!

[bjthehun]

I really like this so far. It would be nice to have another builder-like pattern for the environments as well. Especially to avoid the otherwise required merges to achieve maybes/sets of values.

OK.

[EagleoutIce]

Thank you!!

[EagleoutIce]

This pull request is included in v1.4.2 (see Release v1.4.2 (Dropping xmlparsedata, Benchmark Re-Runs, and Repl Fixes)).

[EagleoutIce]

This pull request is included in v1.4.2 (see Release v1.4.2 (Dropping xmlparsedata, Benchmark Re-Runs, and Repl Fixes)).