rose suite-run: validate in strict mode.

Applies to the suite engine configuration only.
Merge branch 'master' into 54.suite-run.validate.strict
Merge branch 'master' into 54.suite-run.validate.strict
Merge branch 'master' into 54.suite-run.validate.strict
Merge branch 'master' into 54.suite-run.validate.strict
Minor logic improvement and comment fix.
Merge pull request #422 from matthewrmshin/54.suite-run.validate.strict

rose suite-run: validate in strict mode.