Stop duplicating binders in loadLocalModule (#2564)

Since the refactor in c8f2bbd
`loadLocalModule` was duplicating all (top level) binders contained
in local modules.
Because `loadExternalExprs` already puts all `binders` in `loaded0`.

This led to duplicate PrimGuard warnings like seen in #2561 and possibly
more duplicate work elsewhere.

Fixes #2561

clash-ghc/src-ghc/Clash/GHC/LoadModules.hs

@@ -518,7 +518,7 @@ loadLocalModule hdl modName = do
   localPrims <- findPrimitiveAnnotations hdl binderIds
   let loaded1 = loaded0{lbPrims=lbPrims loaded0 <> Seq.fromList localPrims}
 
-  let allBinders = concat binders ++ makeRecursiveGroups (Map.assocs (lbBinders loaded0))
+  let allBinders = makeRecursiveGroups (Map.assocs (lbBinders loaded0))
   pure (rootIds, modFamInstEnvs', rootModule, loaded1, allBinders)
 
 nameString :: Name.Name -> String