www/php71-opcache: Fix upstream bugs causing problems with nextcloud

The bug floods the error logs of not only Nextcloud, but also
Magento and some other applications. While there is already a fix
the next PHP Release is expected at the end of January.

Therefore add the upstream patches.

More details can be found here:
https://bugs.php.net/bug.php?id=75570
https://bugs.php.net/bug.php?id=75608

Reported by: Troels Just <troels@troelsjust.dk>
MFH: 2017Q4