Fix casting error in CrySLParser.java on cryslhandler

[enriozuni]

Description

This PR fixes a casting error on cryslhandler module because the static analysis and code generation components of CogniCrypt were not working.

Type of change

• [X] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

How Has This Been Tested?

Manual tests have been performed for the static analysis part, as well as the code generation one.

Test Configuration:

• Eclipse Version: 2020-06
• Java Version: 1.8
• OS: Windows 10

Checklist:

• [ ] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes

[schlichtig]

@enriozuni can you check the build error?

[enriozuni]

@schlichtig sure.