RFR: JDK-8240970: Some tests fail when run with JCov

[Vicente Romero]

Please review fix for [1] at [2]. The intention of these fix is to be 
able to have clean jcov results when executing langtools tests. As 
explained in the JIRA entry, when running tests with jcov, a number of 
tests fail because some env variables used to run tests under jcov cause 
the runtime to emit non-suppressible warnings. These warnings can affect 
tests that check the output to be as expected. There are other issues we 
found like a dependency jcov has on java.logging which they will be 
trying to eliminate. This dependency was the case of the failure for 
test: tools/jdeps/modules/CheckModuleTest.java. The current solution is 
to ignore that dependency. We should be able to restore the test to its 
original form once this bug has been fixed in jcov.

Thanks,
Vicente

[1] https://bugs.openjdk.java.net/browse/JDK-8240970
[2] http://cr.openjdk.java.net/~vromero/8240970/webrev.00/