3396813 : returned FALSE instead of an empty array in Config Split.

Closes #3396813

src/Plugin/ConfigFilter/SplitFilter.php

@@ -353,7 +353,7 @@ protected function calculateBlacklist() {
 
     if (empty($blacklist) && empty($extensions)) {
       // Early return to short-circuit the expensive calculations.
-      return [];
+      return FALSE;
     }
 
     $blacklist = array_filter($this->manager->getConfigFactory()->listAll(), function ($name) use ($extensions, $blacklist) {
@@ -386,7 +386,7 @@ protected function calculateGraylist() {
 
     if (empty($graylist)) {
       // Early return to short-circuit the expensive calculations.
-      return [];
+      return FALSE;
     }
 
     $graylist = array_filter($this->manager->getConfigFactory()->listAll(), function ($name) use ($graylist) {