MDL-78167 lib: Added missing class properties in tests

In PHP 8.2 and later, setting a value to an undeclared class property is
deprecated and emits a deprecation notice.
So we need to add missing class properties that still need to be declared.

Adding @runTestsInSeparateProcesses and removing setUp() and tearDown() at the
component_test.php, so the test will run in a separate process making sure that
whatever changes happen to the in-memory version of the component class in its thread,
therefore does not impact other tests and makes it more safe.

lib/classes/plugininfo/base.php

@@ -77,6 +77,12 @@ abstract class base {
     /** @var int Move a plugin down in the plugin order */
     public const MOVE_DOWN = 1;
 
+    /** @var array hold $plugin->supported in version.php */
+    public $supported;
+
+    /** @var int hold $plugin->incompatible in version.php  */
+    public $incompatible;
+
     /**
      * Whether this plugintype supports its plugins being disabled.
      *