[CodeCompletion] Don't try to re-typecheck ClosureExpr

At the every usage of 'collectPossibleReturnTypesFromContext()', the
closure must have been typechecked earlier. If the closure has no
valid type at this point, there's no chance to be type-checked by
re-typechecking.

rdar://problem/74430478

Author: rintaro

lib/IDE/ExprContextAnalysis.cpp

@@ -315,10 +315,6 @@ void swift::ide::collectPossibleReturnTypesFromContext(
   }
 
   if (auto ACE = dyn_cast<AbstractClosureExpr>(DC)) {
-    // Try type checking the closure signature if it hasn't.
-    if (!ACE->getType())
-      swift::typeCheckASTNodeAtLoc(ACE->getParent(), ACE->getLoc());
-
     // Use the type checked type if it has.
     if (ACE->getType() && !ACE->getType()->hasError() &&
         !ACE->getResultType()->hasUnresolvedType()) {