core: Add and handle AP_GETLINE_NOSPC_EOL flag in ap_rgetline_core().

This tells the ap_getline() family of functions to consume the end of line
when the buffer is exhausted.

PR 62198.



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1829557 13f79535-47bb-0310-9956-ffa450edef68