Fix CI test FAIL: 015111.nr_ulsim.test8
This Merge Request should solve the test FAIL: 015111.nr_ulsim.test8 - Test8: DMRS Type B, 3 DMRS, 2 PTRS, 7 Interpolated Symbols. There were PTRS symbols in DMRS symbols. Moreover, the computation of number of DMRS symbols in nr_ulsim was wrong.