Updated configuration to enable strictMode unit testing with Maven

[marilynel]

#953
Execute the test suite in strict mode with Maven:
mvn test -P test-strict-mode

[stleary]

What problem does this code solve?
Strict mode testing should be available in Maven, in addition to Gradle

Does the code still compile with Java6?
Yes

Risks
Low

Changes to the API?
No

Will this require a new release?
No

Should the documentation be updated?
No

Does it break the unit tests?
No

Was any code refactored in this commit?
No

Review status
APPROVED

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