Add a new test for the handling connections marked as 'close' by the server.
Add a new test for the handling connections marked as 'close' by the server.

* test/test_context.c
  (test_serf_closed_connection): add new test.
  (test_context): run the new test.

SirJson/serf,justinweb/serf,sworda/serf,muthusuba/serf,stoneCC/serf,pengdu/serf,lazysoez/serf,sworda/serf,liuzongquan/serf,zhupan/serf,x-clone/serf,Manouchehri/serf,soufianeEL/serf,lazysoez/serf,sworda/serf,TommyU/serf,justinweb/serf,zhupan/serf,stoneCC/serf,stoneCC/serf,muthusuba/serf,KyleSanderson/serf,Manouchehri/serf,blueszhangsh/serf,idomon/serf,blueszhangsh/serf,zhengcq315/serf,justinweb/serf,SirJson/serf,soufianeEL/serf,alex1818/serf,zhengcq315/serf,blueszhangsh/serf,muthusuba/serf,pengdu/serf,x-clone/serf,krime/serf,alex1818/serf,zhengcq315/serf,x-clone/serf,alex1818/serf,soufianeEL/serf,krime/serf,krime/serf,google-code-export/serf,zhengcq315/serf,lazysoez/serf,Manouchehri/serf,liuzongquan/serf,blueszhangsh/serf,KyleSanderson/serf,wzugang/serf,idomon/serf,yesoce/serf,KyleSanderson/serf,soufianeEL/serf,SirJson/serf,google-code-export/serf,wzugang/serf,wzugang/serf,SirJson/serf,TommyU/serf,TommyU/serf,yesoce/serf,lazysoez/serf,alex1818/serf,Manouchehri/serf,google-code-export/serf,zhupan/serf,stoneCC/serf,zhupan/serf,sworda/serf,wzugang/serf,idomon/serf,KyleSanderson/serf,liuzongquan/serf,pengdu/serf,justinweb/serf,yesoce/serf,TommyU/serf,google-code-export/serf,liuzongquan/serf,pengdu/serf,krime/serf,muthusuba/serf,x-clone/serf,yesoce/serf,idomon/serf