[K/N][perf] Return doLast

This fixes failures in performance builds caused by the KT-MR-13291 "Update Gradle to 8.4"
doLast { } block here is necessary as soon as it should be run during the task execution, while without it is a configuration time. Performance builds invoke Gradle several times with different tasks and parameters. The change in the mentioned MR made one of the invocations remove the nativeReports.json file produced earlier.

Merge-request: KT-MR-13496
Merged-by: Pavel Punegov <Pavel.Punegov@jetbrains.com>

kotlin-native/performance/build.gradle

@@ -121,7 +121,9 @@ task clean {
             dependsOn "${it.path}:clean"
         }
     }
-    delete(layout.buildDirectory)
+    doLast {
+        delete(layout.buildDirectory)
+    }
 }
 
 defaultTasks 'konanRun'