[php-src] Issue #12724: strtotime() doesnt return false when a timestamp input given.

Issue: https://github.com/php/php-src/issues/12724 Author: MMMahmoodian ### Description The following code: ```php <?php var_dump(strtotime(1700394677)); ``` Resulted in this output: ``` int(85452598839) ``` But I expected this output instead: ``` bool(false) ``` Extra context: We have a code that checks whether an input is either a UNIX timestamp or datetime. We were using strtotime() to check if the input is datetime or not. This morning we faced many errors due to this bug. strtotime should return false because this is not a standard date format. After some trial and error I found out strtotime processes input like this: HHiissYYYY. Whenever the input timestamps have the following conditions the error occurs: HH less than 24, ii less than 60, and 'ss' less than 61. In the given example 17 is less than 24, 00 is less than 60, and 39 is less than 61 so the error occurs. In all the following inputs the function works as expected: ``` 2500394677 1760394677 1700614677 ``` This isn't a PHP 8 issue and as far as I tested it exists in all versions(5.6, 7.4, 8). I would be happy to help if needed. ### PHP Version 8.0.30 ### Operating System _No response_