This allows us to exclude matches of certain patterns in
invertedTests, ignoredTests, unreliableTests, and suspendedTests.
To use this new functionality, prefix "!" to the pattern.
This functionality serves as a workaround in some cases to not being
able to use advanced regular expression techniques, such as
"negative lookahead", with CMake's regular expression engine.
Output of "ctest -N" is unchanged by this commit.
This functionality will be used soon (see next commits).