[Performance] [VendorLocker] Early allow change return type on privat…

…e method on ClassMethodReturnTypeOverrideGuard::shouldSkipClassMethod() (#5642)

src/VendorLocker/NodeVendorLocker/ClassMethodReturnTypeOverrideGuard.php

@@ -32,6 +32,11 @@ public function shouldSkipClassMethod(ClassMethod $classMethod, Scope $scope): b
             return true;
         }
 
+        // early allow add return type on private method
+        if ($classMethod->isPrivate()) {
+            return false;
+        }
+
         $classReflection = $this->reflectionResolver->resolveClassReflection($classMethod);
         if (! $classReflection instanceof ClassReflection) {
             return true;