`dl()` under Win + ZTS/opcache has some refcouting issue

[mvorisek]

Description

See https://ci.appveyor.com/project/php/php-src/builds/44749597/job/xyq7uuqg5mxe5874#L1667

Fatal error: Internal zvals cannot be refcounted in Unknown on line 0

code/commit to reproduce in CI: 753a143

a) I would expect no refcounting error.
b) I would expect dl() to not produce a fatal error, but instead a warning and return false.

PHP Version

master, maybe other branches as well

not sure about the exact conditions to reproduce, but the NTS build /wo opcache does not have this problem

Operating System

Win + ZTS

[cmb69]

See #8508, which is basically a duplicate of #9196.