junit: Add properties to the JUnit.xml file

[Ankita13-code]

• In case of CVM test cases, we need the information about vmsize and disk_encryption status in the JUnit.xml file for testing it on different combinations.
• This PR adds these values to the JUnit.xml file in the form of system properties by extracting it from the information in the TestResultMessageBase class.
• In future, this method can also be used to add more properties to the Junit file if required