THRIFT-5934: Fix deprecated usage of ReflectionProperty::setAccessible() in PHP tests

[pkvach]

Running PHPUnit tests on PHP 8.5 produces deprecation warnings related to usage of ReflectionProperty::setAccessible().

Example failure:

PHP Deprecated: Method `ReflectionProperty::setAccessible()` is deprecated since 8.5, as it has no effect since PHP 8.1

According to official PHP documentation, ReflectionProperty::setAccessible() is deprecated as of PHP 8.5 and has had no effect since PHP 8.1, where all properties are accessible by default.
https://www.php.net/manual/en/reflectionproperty.setaccessible.php

Note

This will not affect earlier PHP versions, meaning the changes are backward compatible.

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• If a ticket exists: Does your pull request title follow the pattern "THRIFT-NNNN: describe my issue"?
• Did you squash your changes to a single commit? (not required, but preferred)
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• If your change does not involve any code, include [skip ci] anywhere in the commit message to free up build resources.

[sveneld]

LGTM.

[Jens-G]

Run vendor/bin/phpunit -c lib/php/phpunit.xml
PHPUnit 7.5.20 by Sebastian Bergmann and contributors.

........E

Time: 633 ms, Memory: 12.00 MB

There was 1 error:

1) Test\Thrift\Unit\Lib\Factory\TBinaryProtocolFactoryTest::testGetProtocol with data set "allTrue" (true, true)
TypeError: Argument 1 passed to Test\Thrift\Unit\Lib\Factory\TBinaryProtocolFactoryTest::getPropertyValue() must be an instance of Test\Thrift\Unit\Lib\object, instance of Thrift\Protocol\TBinaryProtocol given, called in /home/runner/work/thrift/thrift/lib/php/test/Unit/Lib/Factory/TBinaryProtocolFactoryTest.php on line 50

/home/runner/work/thrift/thrift/lib/php/test/Unit/Lib/ReflectionHelper.php:53
/home/runner/work/thrift/thrift/lib/php/test/Unit/Lib/Factory/TBinaryProtocolFactoryTest.php:50

ERRORS!
Tests: 9, Assertions: 25, Errors: 1.

[pkvach]

Run vendor/bin/phpunit -c lib/php/phpunit.xml
PHPUnit 7.5.20 by Sebastian Bergmann and contributors.

........E

Time: 633 ms, Memory: 12.00 MB

There was 1 error:

1) Test\Thrift\Unit\Lib\Factory\TBinaryProtocolFactoryTest::testGetProtocol with data set "allTrue" (true, true)
TypeError: Argument 1 passed to Test\Thrift\Unit\Lib\Factory\TBinaryProtocolFactoryTest::getPropertyValue() must be an instance of Test\Thrift\Unit\Lib\object, instance of Thrift\Protocol\TBinaryProtocol given, called in /home/runner/work/thrift/thrift/lib/php/test/Unit/Lib/Factory/TBinaryProtocolFactoryTest.php on line 50

/home/runner/work/thrift/thrift/lib/php/test/Unit/Lib/ReflectionHelper.php:53
/home/runner/work/thrift/thrift/lib/php/test/Unit/Lib/Factory/TBinaryProtocolFactoryTest.php:50

ERRORS!
Tests: 9, Assertions: 25, Errors: 1.

Fixed the test failure in the latest commit, thanks!