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 union3;

union vec3
{
    struct { float x,y,z; }
    float[3] xyz;
}

void main()
{
    vec3 v;
    assert(&v.y is &v.xyz[1]);
}