Update test run generator

[LaurenWags]

Fix #542

Per the above issue,

• commented out the ability to generate the "Reduced" set of test cases for both Desktop and Android as we no longer have designated mid-cycle maintenance releases where these reduced cases were used. Now, we will have the full manual pass (to be run for each major chromium bump version) and a set of basic checks which will be run for each hotfix (whether it contains a minor chromium bump or not).
• updated the generation of manual passes to now create a Linux test run for the basic checks

[stephendonner]

This LGTM 👍

I checked for any obvious typos, saw none, and also verified the variables match, but I didn't run the patch locally, and defer ultimately to @kjozwiak

[kjozwiak]

LGTM 👍 Went through all the choices using --test true and everything worked/generated without issues. Nicely done.