cInitializer(): Only try hArrayInit() for vars/fields, not for params

Since 53c39679 cInitializer() called hArrayInit() on PARAM symbols,
causing illegal accesses to FBSYMBOL.var_.* fields that PARAMs do not use.
(uninitialized memory accesses detected via valgrind)

To fix this cInitializer() will only call hArrayInit() on FBSYMBOLs that
actually use the FBSYMBOL.var_.* fields (VARs and FIELDs), and use
hUDTInit() or hElmInit() for others (such as PARAMs).
This even makes sense because parameters cannot be fixed-size arrays
anyways, thus we don't need to bother parsing array initializers for them.