Issue #2829346 by ekes, kentr, klausi: Allow repeated calls to DrupalKernel::setSitePath()

core/lib/Drupal/Core/DrupalKernel.php

@@ -410,7 +410,7 @@ public static function findSitePath(Request $request, $require_settings = TRUE,
    * {@inheritdoc}
    */
   public function setSitePath($path) {
-    if ($this->booted) {
+    if ($this->booted && $path !== $this->sitePath) {
       throw new \LogicException('Site path cannot be changed after calling boot()');
     }
     $this->sitePath = $path;

core/tests/Drupal/KernelTests/Core/DrupalKernel/DrupalKernelTest.php

@@ -184,6 +184,11 @@ public function testPreventChangeOfSitePath() {
       $pass = TRUE;
     }
     $this->assertTrue($pass, 'Throws LogicException if DrupalKernel::setSitePath() is called after boot');
+
+    // Ensure no LogicException if DrupalKernel::setSitePath() is called with
+    // identical path after boot.
+    $path = $kernel->getSitePath();
+    $kernel->setSitePath($path);
   }
 
 }