Removes duplicate struct entries, changes struct field sizes and reorder them a bit. Cuts off 136 bytes from the
From 1832 bytes with 5 "holes" in my build before this PR. At 1696 bytes with one hole afterward.
... and rely only on the value already set in Curl_easy.
As the info is already stored in the transfer handle anyway, there's no need to carry around a duplicate buffer for the life-time of the handle. Closes #6534
... and rely only on the value already set in Curl_easy. Closes #6534