Fix a double-free bug in -fexternal-interpreter

Originally I planned to make this reference manually managed, but it
looks like at some point I gave it a finalizer on the GHC side, but
forgot to remove the manual free here.  The result is that ghc-iserv
could crash in getStablePtr sometimes when using TH.

libraries/ghci/GHCi/TH.hs

@@ -132,7 +132,6 @@ finishTH pipe rstate = do
   qstateref <- localRef rstate
   qstate <- readIORef qstateref
   _ <- runGHCiQ runModFinalizers qstate { qsPipe = pipe }
-  freeRemoteRef rstate
   return ()
 
 runTH