Auto merge of #25754 - geofft:remove-compiletest-jit, r=alexcrichton
Auto merge of #25754 - geofft:remove-compiletest-jit, r=alexcrichton

jit support was removed from rustc in 6b34ba242d7372b779bf50682b9401b61183828e
(December 2013), so passing `--jit` wouldn't even work.

pshc/rust,GBGamer/rust,reem/rust,mvdnes/rust,dwillmer/rust,aidancully/rust,l0kod/rust,nwin/rust,vhbit/rust,jroesch/rust,graydon/rust,vhbit/rust,GBGamer/rust,graydon/rust,jroesch/rust,nwin/rust,reem/rust,aidancully/rust,dwillmer/rust,graydon/rust,jashank/rust,zubron/rust,pshc/rust,vhbit/rust,reem/rust,zubron/rust,nwin/rust,jroesch/rust,jashank/rust,GBGamer/rust,pshc/rust,GBGamer/rust,zubron/rust,aidancully/rust,mvdnes/rust,dwillmer/rust,zubron/rust,reem/rust,zubron/rust,nwin/rust,aidancully/rust,pshc/rust,dwillmer/rust,pshc/rust,reem/rust,jroesch/rust,l0kod/rust,l0kod/rust,vhbit/rust,jroesch/rust,zubron/rust,pshc/rust,dwillmer/rust,l0kod/rust,vhbit/rust,l0kod/rust,jashank/rust,vhbit/rust,graydon/rust,vhbit/rust,mvdnes/rust,zubron/rust,aidancully/rust,mvdnes/rust,dwillmer/rust,aidancully/rust,mvdnes/rust,dwillmer/rust,dwillmer/rust,nwin/rust,jashank/rust,jashank/rust,nwin/rust,reem/rust,mvdnes/rust,nwin/rust,jashank/rust,jroesch/rust,l0kod/rust,GBGamer/rust,GBGamer/rust,GBGamer/rust,graydon/rust,GBGamer/rust,nwin/rust,l0kod/rust,pshc/rust,jashank/rust,jroesch/rust,jroesch/rust,l0kod/rust,jashank/rust,zubron/rust,pshc/rust,graydon/rust,vhbit/rust