Revert "PrintAsClang: Apply review comments to check on should print of @cdecl"

This reverts commit 3623c1d.

Author: hamishknight

lib/PrintAsClang/DeclAndTypePrinter.cpp

@@ -3006,22 +3006,14 @@ bool DeclAndTypePrinter::shouldInclude(const ValueDecl *VD) {
       return false;
   }
 
-  // In C output mode print only the C variant `@cdecl` (no `@_cdecl`),
-  // while in other modes print only `@_cdecl`.
-  std::optional<ForeignLanguage> cdeclKind = std::nullopt;
-  if (auto *FD = dyn_cast<AbstractFunctionDecl>(VD))
-    cdeclKind = FD->getCDeclKind();
-  if (cdeclKind &&
-      (*cdeclKind == ForeignLanguage::C) !=
-       (outputLang == OutputLanguageMode::C))
+  // In C output mode print only @cdecls and skip them in other modes.
+  bool isCDeclForC = false;
+  auto *FD = dyn_cast<AbstractFunctionDecl>(VD);
+  if (FD)
+    isCDeclForC = FD->getCDeclKind() == ForeignLanguage::C;
+  if (isCDeclForC != (outputLang == OutputLanguageMode::C))
     return false;
 
-  // C output mode only accepts @cdecl functions.
-  if (outputLang == OutputLanguageMode::C &&
-      !cdeclKind) {
-    return false;
-  }
-
   if (VD->getAttrs().hasAttribute<ImplementationOnlyAttr>())
     return false;