traits test: convert to new unittest macros

Signed-off-by: Matthias Kretz <kretz@kde.org>
traits test: add more tests

test for
* has_subscript_operator
* has_multiply_operator
* has_equality_operator
* is_simd_mask
* is_simd_vector

Signed-off-by: Matthias Kretz <kretz@kde.org>