Skip StandaloneLinePlainConstructorParamFixer for 3 or fewer params

[TomasVotruba]

StandaloneLinePlainConstructorParamFixer now only splits constructors with 4 or more parameters. Short parameter lists stay readable on a single line.

Skipped:

final class SkipThreeParams
{
    public function __construct(CorePermissions $security, Translator $translator, RouterInterface $router)
    {
    }
}

Still fixed:

 final class PlainParams
 {
-    public function __construct(CorePermissions $security, Translator $translator, RouterInterface $router, Logger $logger)
+    public function __construct(
+        CorePermissions $security,
+        Translator $translator,
+        RouterInterface $router,
+        Logger $logger
+    )
     {
     }
 }

Param counting ignores tokens nested in default values, so [1, 2] or new Foo(1) defaults do not inflate the count. The previous empty-param-list guard is subsumed by the count check.