[php-src] Issue #9930: Constant causes an uncatchable fatal error when given non-existent class

Issue: https://github.com/php/php-src/issues/9930 Author: ciaranmcnulty ### Description The following code: ```php var_dump(defined('Foo::foo')); try { $class = constant('Foo::foo'); } catch (\Throwable $e) { echo "I caught it!"; } ``` Resulted in this output: ``` bool(false) Fatal error: Class "Foo" not found in /in/7tWT2 on line 6 Process exited with code 255. ``` But I expected this output instead: ``` bool(false) I caught it! ``` i.e. the error should be caught as a throwable Error, as is the behaviour of constant since 8.0.0 ### PHP Version PHP 8.1.12 ### Operating System _No response_