Improve error_handing replacement functions

We explicitly skip calls to user_error_handler in EH_THROW mode

Closes GH-6050.

Zend/zend_API.c

@@ -4230,62 +4230,25 @@ ZEND_API void zend_save_error_handling(zend_error_handling *current) /* {{{ */
 {
 	current->handling = EG(error_handling);
 	current->exception = EG(exception_class);
-	ZVAL_COPY(&current->user_handler, &EG(user_error_handler));
+	ZVAL_UNDEF(&current->user_handler);
 }
 /* }}} */
 
 ZEND_API void zend_replace_error_handling(zend_error_handling_t error_handling, zend_class_entry *exception_class, zend_error_handling *current) /* {{{ */
 {
 	if (current) {
 		zend_save_error_handling(current);
-		if (error_handling != EH_NORMAL && Z_TYPE(EG(user_error_handler)) != IS_UNDEF) {
-			zval_ptr_dtor(&EG(user_error_handler));
-			ZVAL_UNDEF(&EG(user_error_handler));
-		}
 	}
+	ZEND_ASSERT(error_handling == EH_THROW || exception_class == NULL);
 	EG(error_handling) = error_handling;
-	EG(exception_class) = error_handling == EH_THROW ? exception_class : NULL;
-}
-/* }}} */
-
-static int same_zval(zval *zv1, zval *zv2)  /* {{{ */
-{
-	if (Z_TYPE_P(zv1) != Z_TYPE_P(zv2)) {
-		return 0;
-	}
-	switch (Z_TYPE_P(zv1)) {
-		case IS_UNDEF:
-		case IS_NULL:
-		case IS_FALSE:
-		case IS_TRUE:
-			return 1;
-		case IS_LONG:
-			return Z_LVAL_P(zv1) == Z_LVAL_P(zv2);
-		case IS_DOUBLE:
-			return Z_LVAL_P(zv1) == Z_LVAL_P(zv2);
-		case IS_STRING:
-		case IS_ARRAY:
-		case IS_OBJECT:
-		case IS_RESOURCE:
-			return Z_COUNTED_P(zv1) == Z_COUNTED_P(zv2);
-		default:
-			return 0;
-	}
+	EG(exception_class) = exception_class;
 }
 /* }}} */
 
 ZEND_API void zend_restore_error_handling(zend_error_handling *saved) /* {{{ */
 {
 	EG(error_handling) = saved->handling;
-	EG(exception_class) = saved->handling == EH_THROW ? saved->exception : NULL;
-	if (Z_TYPE(saved->user_handler) != IS_UNDEF
-		&& !same_zval(&saved->user_handler, &EG(user_error_handler))) {
-		zval_ptr_dtor(&EG(user_error_handler));
-		ZVAL_COPY_VALUE(&EG(user_error_handler), &saved->user_handler);
-	} else if (Z_TYPE(saved->user_handler)) {
-		zval_ptr_dtor(&saved->user_handler);
-	}
-	ZVAL_UNDEF(&saved->user_handler);
+	EG(exception_class) = saved->exception;
 }
 /* }}} */