Test labels are incorrect

[mwestphal]

Describe the bug
Test labels to be used with ctest are incorrect:

• Multiple labels are not correctly taken into account

ctest -L occt

Does not run all occt tests because some tests are labelled manually with multiple labels, which does not work, it should.

• File extensions are not correctly taken into account

If a file contains file.foo.ext, then the label for this test is fooext, it should be ext