CORESET start multiple of 6 fix
According to the standard any CORESET (except CSET0) would always start
from the first common resource block index which is multiple of 6 in the
BWP. This was not taken into account in the code. The BWP switch CI test
is modified to test a BWP start not multiple of 6.
An exception is the case where rb-Offset-r16 parameter is set, but can't
be used at gNB for FAPI compatibility.
Closes: #1037