[CodeComplete] Remove a redundant bit of logic

`getTypeForCompletion` already falls back to the
contextual type, and querying the ConstraintSystem
for this is wrong since it may not be in the same
state as it was when the Solution was produced.

Author: hamishknight

lib/IDE/PostfixCompletion.cpp

@@ -178,8 +178,6 @@ void PostfixCompletionCallback::sawSolutionImpl(
   auto *Locator = CS.getConstraintLocator(SemanticExpr);
   Type ExpectedTy = getTypeForCompletion(S, CompletionExpr);
   Expr *ParentExpr = CS.getParentExpr(CompletionExpr);
-  if (!ParentExpr && !ExpectedTy)
-    ExpectedTy = CS.getContextualType(CompletionExpr, /*forConstraint=*/false);
 
   auto *CalleeLocator = S.getCalleeLocator(Locator);
   ValueDecl *ReferencedDecl = nullptr;