[jnc_rt] opt: GcHeap::collect_l should use StdType_AbstractClassPtr instead of precise class pointer
[jnc_rt] opt: GcHeap::collect_l should use StdType_AbstractClassPtr instead of precise class pointer

this way we likely reduce the overall number of types in the module

vovkos/jancy,vovkos/jancy,vovkos/jancy,vovkos/jancy,vovkos/jancy