test: reset PHP versions after each test class

Required, as test success is currently order-dependent
and may prevent running specific subgroups of tests.

The reason being that the PHP version is set via simple
parameters, which are global and previously unable to be
unset. Some tests required setting the specific version of PHP,
which would end up pinning that version until the next test
that required a specific version. If the prior version was too
low, it could cause later tests not to execute at all, breaking
things.

You could not set the version parameter to `null`
because it's always accessed via `provideIntParameter(...)`,
which does type-checking.

Author: Kenneth-Sills

src/Configuration/Parameter/SimpleParameterProvider.php

@@ -39,6 +39,14 @@ public static function setParameter(string $name, mixed $value): void
         self::$parameters[$name] = $value;
     }
 
+    /**
+     * @param Option::* $name
+     */
+    public static function unsetParameter(string $name): void
+    {
+        unset(self::$parameters[$name]);
+    }
+
     /**
      * @param Option::* $name
      * @return mixed[]

src/Testing/PHPUnit/AbstractRectorTestCase.php

@@ -50,6 +50,8 @@ abstract class AbstractRectorTestCase extends AbstractLazyTestCase implements Re
      */
     public static function tearDownAfterClass(): void
     {
+        SimpleParameterProvider::unsetParameter(Option::PHP_VERSION_FEATURES);
+
         SimpleParameterProvider::setParameter(Option::AUTO_IMPORT_NAMES, false);
         SimpleParameterProvider::setParameter(Option::AUTO_IMPORT_DOC_BLOCK_NAMES, false);
         SimpleParameterProvider::setParameter(Option::REMOVE_UNUSED_IMPORTS, false);