Don't run killAllSessions on serverless

Author: alcaeus

tests/SpecTests/TransactionsSpecTest.php

@@ -316,6 +316,11 @@ protected function createTestCollection(): void
      */
     private static function killAllSessions(): void
     {
+        // killAllSessions is not supported on serverless, see CLOUDP-84298
+        if (static::isServerless()) {
+            return;
+        }
+
         $manager = static::createTestManager();
         $primary = $manager->selectServer(new ReadPreference('primary'));
 

tests/UnifiedSpecTests/UnifiedTestRunner.php

@@ -78,7 +78,7 @@ public function __construct(string $internalClientUri)
         /* Atlas prohibits killAllSessions. Inspect the connection string to
          * determine if we should avoid calling killAllSessions(). This does
          * mean that lingering transactions could block test execution. */
-        if (strpos($internalClientUri, self::ATLAS_TLD) !== false) {
+        if ($this->isServerless() || strpos($internalClientUri, self::ATLAS_TLD) !== false) {
             $this->allowKillAllSessions = false;
         }
     }