[tools] Fix data dictionary builder testname logic

[zaliqarosli]

Brief summary of changes

The instruments are separated by a delimiter {-@-} in ip_output.txt via the lorisform_parser for PHP instruments. but there's no way of ensuring this for linst instruments (and its not specified in the wiki). therefore, linst instruments aren't handled separately in the instrument for loop.

because of this, the data dictionary builder breaks for linst instruments as the $testname stays stuck on the first instruments'. this PR does a quick fix to make sure that the $testname variables is correctly re-defined when a table or testname components appears in ip_output.txt

• [ ] Have you updated related documentation?

Testing instructions (if applicable)

Link(s) to related issue(s)

• Resolves # (Reference the issue this fixes, if any.)