The search order for DLLs on Windows is (simplified):
* the application folder
* the system folder
* all folders in the `PATH`
(The full details are documented on Microsoft Learn[1].)
As is, we're adding `deps\bin` to the `PATH` when running the tests,
but any DLLs in the system folder take precedence, so these would be
used instead of our intended dependencies. To mitigate that, we copy
over all DLLs from `deps\bin` to our application folder (i.e. where
php.exe, php-cgi.exe and phpdbg.exe are placed).
Since we're doing this, there is no more need to attempt to remove the
OpenSSL DLLs in the system folder (what seems to be a bad idea anyway).
[1] <https://learn.microsoft.com/en-us/windows/win32/dlls/dynamic-link-library-search-order>
Closes GH-17805.
Christoph M. Becker