[DowngradePhp73] Add DowngradePhp73JsonConstRector

[samsonasik]

Add DowngradePhp73JsonConstRector for downgrade JSON_THROW_ON_ERROR constant.

Fixes rectorphp/rector#6931

[samsonasik]

/cc @rs-ubaldi

[samsonasik]

All checks have passed 🎉 @TomasVotruba I think it is ready.

[samsonasik]

I am merging it ;)

[samsonasik]

It seems we need to handling constant exists check, like:

2) vendor/clue/ndjson-react/src/Decoder.php:36
    ---------- begin diff ----------
@@ @@
             throw new \BadMethodCallException('Options parameter is only supported on PHP 5.4+');
         }
         if (\defined('JSON_THROW_ON_ERROR')) {
-            $options = $options & ~\JSON_THROW_ON_ERROR;
+            $options = $options & ~0;
         }

on current scoped downgrade, ref rectorphp/rector@adcb702#diff-5296e05dc788634e5de6fe389ae1bb99dd50ad8da693877b91bfde3ecf96c41a

[TomasVotruba]

Thanks 👏 😎

[rs-ubaldi]

This is awesome thank you guys for finalizing this :-)