resume: consider a resume from [content-length] to be OK

Basically since servers often then don't respond well to this and
instead send the full contents and then libcurl would instead error out
with the assumption that the server doesn't support resume. As the data
is then already transfered, this is now considered fine.

Test case 1434 added to verify this. Test case 1042 slightly modified.

Reported-by: hugo
Bug: http://curl.haxx.se/bug/view.cgi?id=1443

tests/data/test1042

@@ -56,10 +56,10 @@ Content-Type: text/plain
 http
 </server>
  <name>
-HTTP GET from end of entirely-downloaded file, no server resume
+HTTP GET beyond end of entirely-downloaded file, no server resume
  </name>
  <command>
-http://%HOSTIP:%HTTPPORT/1042 -C -
+http://%HOSTIP:%HTTPPORT/1042 -C 200
 </command>
 <file name="log/curl1042.out">
 012345678
@@ -85,7 +85,7 @@ http://%HOSTIP:%HTTPPORT/1042 -C -
 </strip>
 <protocol>
 GET /1042 HTTP/1.1
-Range: bytes=100-
+Range: bytes=200-
 Host: %HOSTIP:%HTTPPORT
 Accept: */*