FIX: Handle case of old-style revisit records that have no status or body. Check for Content-Length: 0 in warc revisit records' headers and if so,
set headers to null. In AccessPoint, set httpHeadersResource = payloadResource for this case
FIX: Resource.getRecordLength() returns warc/arc content length. No additional parsing is done if the record is empty
For revisits, set http headers resource to payload resource
Merge branch 'topic/non-response-support'
FIX: Close old httpHeadersResource before setting httpHeadersResource = payloadResource