* fix(testing): update maxWorkers jest builder option to support string type
Jest supports both number and string args for the maxWorkers option, per their latest docs. This
updates the options for the jest builder to support both number and string types. Also updates the
docs accordingly.
ISSUES CLOSED: #2871
* fix(testing): fix test expectation missing property
the --coverage option was not being used in the builder at all, so provided no change in behavior.
The --codeCoverage option should be used instead
ISSUES CLOSED: #2564
