Describe the bug
ut_sonar_test_reporter can produce invalid output on failing tests with long failure message.

The error that we see in sonar-scanner is:

Look at the SonarQube documentation to know the expected XML format. [com.ctc.wstx.exc.WstxLazyException] Unexpected character (CTRL-CHAR, code 10); expected a semi-colon after the reference for entity 'lt'
[ERROR] at [row,col {unknown-source}]: [4670,4001]

Provide version info
Running on latest utPLSQL v3.1.6

Information about client software
Not relevant

To Reproduce
Have a test that is failing and produces more than 4000 chars of output data and be unlucky enough to get the < string at 4000 chars so the reporter inserts a line break.

Example:

   ... <INSERT_TMSTMP>2018-07-28T01:01:37.092127</INSERT_TMSTMP>&lt
;GROUP_ID/>...

Expected behavior
We should probably make the failure message as CDATA rather than escape the chars.