vec_cbind() drops rows with zero column data frames

[DavisVaughan]

I expect 1 row, 0 cols:

vctrs::vec_cbind(vctrs::new_data_frame(n = 1L), vctrs::new_data_frame(n = 1L))
#> data frame with 0 columns and 0 rows

^{Created on 2020-10-16 by the reprex package (v0.3.0.9001)}

Comes up in tune where i make pretty heavy usage of zero col data frames

[DavisVaughan]

I think we just need to pass Rf_ScalarInteger(nrow) through here instead of R_NilValue

vctrs/src/bind.c

Line 480 in e1d02ed

out = vec_restore(out, type, R_NilValue, VCTRS_OWNED_true);