Running Tests docs: quotes for setting env vars in windows

[JeremyMahieu]

Proposed Changes

Place quotes in the correct location. PR #896 was wrong. This should be correct now. Doing it like it is written in the docks now leads to errors because it's already quoted in the code so you end up with tripple quotes.
args = $"/c \"\"{ctl}\" {args}\"";

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[lukebakken]

Checking concourse now