[SUREFIRE-1088] fix handling of @Ignored test cases
Add debug output to Surefire943ReportContentIT for analysis of the failing test in Jenkins
[SUREFIRE-1095] NPE in JUnit 4.x RunListener + Refactoring
[SUREFIRE-963] Unable to set empty environment variables

Fix SUREFIRE-963

Unit test about env variable values completed with the use case of an
env varaible not defined

Apply the maven code style to the previous modifications
[SUREFIRE-817] JUnit 4.7+ Provider and System Exit proved by ITs
[SUREFIRE-1088] alternative fix for handling of @Ignored test cases (the better-safe-than-sorry way)
[SUREFIRE-1088] another alternative fix for handling of @Ignored test cases: seems like the problem was in the NonConcurrentRunListener that did not finish previous test sets in case of test errors.
Multiple lines with " T E S T S" in log.