Force initialize the runtime module in Module::genLLVMModule. It is required for all non-trivial D modules anyway, so why load it lazily? This fixes run/typeid_83.d (DtoDeclareTypeInfo expects runtime to be initialized)

module bug42;

void main() {
    int i = 2;
    switch (i) {
    case 0:
    case 1:
    default:
    }
}