[clang] [clang][Analyzer][NFC] Simplify preDefault/preFseek/preFreadFwrite of StreamChecker (PR #71394)

[Balázs Kéri via cfe-commits]

================
@@ -639,12 +644,7 @@ void StreamChecker::preFreadFwrite(const FnDescription *Desc,
                                    bool IsFread) const {
   ProgramStateRef State = C.getState();
   SVal StreamVal = getStreamArg(Desc, Call);
-  State = ensureStreamNonNull(StreamVal, Call.getArgExpr(Desc->StreamArgNo), C,
-                              State);
-  if (!State)
-    return;
-  State = ensureStreamOpened(StreamVal, C, State);
-  if (!State)
+  if (!basicCheck(Desc, Call, C, State, StreamVal))
----------------
balazske wrote:

```suggestion
  State = ensureStreamNonNullAndOpened(Desc, Call, C, State, StreamVal);
  if (!State)
    return;
```

https://github.com/llvm/llvm-project/pull/71394