Fix ctu_failure test not removing its test folder

[whisperity]

The test workspace has a lingering ctu_failure project folder due to test code layout error.

If you check the output with nocapture=1 in the .noserc (and use the rename of the class in this patch), the following is printed:

Test the failure zip contains the source of imported TU ... Running TestCtuFailure tests in /home/<username>/CodeChecker/codechecker/build/workspace/ctu_failure-s7so2I
'analyze' reported CTU-compatibility? False
Has -analyzer-display-ctu-progress? False
SKIP: CTU is not supported
Test the failure zip contains the source of imported TU and all the ... Running TestCtuFailure tests in /home/<username>/CodeChecker/codechecker/build/workspace/ctu_fail
ure-s7so2I
'analyze' reported CTU-compatibility? False
Has -analyzer-display-ctu-progress? False
SKIP: CTU is not supported
Test that Clang indeed logs the AST import events. ... Running TestCtuFailure tests in /home/<username>/CodeChecker/codechecker/build/workspace/ctu_failure-s7so2I
'analyze' reported CTU-compatibility? False
Has -analyzer-display-ctu-progress? False
SKIP: CTU is not supported
Removing: /home/<username>/CodeChecker/codechecker/build/workspace/ctu_failure-s7so2I
Test full CTU without reparse. ... Running TestCtu tests in /home/<username>/CodeChecker/codechecker/build/workspace/ctu_failure-s7so2I
'analyze' reported CTU-compatibility? False
SKIP: CTU is not supported
Test full CTU with reparse. ... Running TestCtu tests in /home/<username>/CodeChecker/codechecker/build/workspace/ctu_failure-s7so2I
'analyze' reported CTU-compatibility? False
SKIP: CTU is not supported
Test CTU analyze phase without reparse. ... Running TestCtu tests in /home/<username>/CodeChecker/codechecker/build/workspace/ctu_failure-s7so2I
'analyze' reported CTU-compatibility? False
SKIP: CTU is not supported
Test CTU analyze phase with reparse. ... Running TestCtu tests in /home/<username>/CodeChecker/codechecker/build/workspace/ctu_failure-s7so2I
'analyze' reported CTU-compatibility? False
SKIP: CTU is not supported
Test CTU collect phase without reparse. ... Running TestCtu tests in /home/<username>/CodeChecker/codechecker/build/workspace/ctu_failure-s7so2I
'analyze' reported CTU-compatibility? False
SKIP: CTU is not supported
Test CTU collect phase with reparse. ... Running TestCtu tests in /home/<username>/CodeChecker/codechecker/build/workspace/ctu_failure-s7so2I
'analyze' reported CTU-compatibility? False
SKIP: CTU is not supported
Removing: /home/<username>/CodeChecker/codechecker/build/workspace/ctu-haeeWw

This means that the TestCtu class is ran in the ctu_failure folder too, because of how the files are laid out. This results in the CTU-FAILURE folder being removed, but then created again.