Document run-cycle backoff reset intent and reduce test flake

Co-authored-by: brendandburns <5751682+brendandburns@users.noreply.github.com>

Author: Copilot

util/src/main/java/io/kubernetes/client/informer/cache/ReflectorRunnable.java

@@ -113,6 +113,8 @@ public ReflectorRunnable(
    */
   public void run() {
     log.info("{}#Start listing and watching...", apiTypeClass);
+    // run() can be invoked multiple times for the same reflector instance; always restart backoff
+    // from the initial value for each list-watch cycle.
     resetWatchRetryBackoff();
 
     try {

util/src/test/java/io/kubernetes/client/informer/cache/ReflectorRunnableTest.java

@@ -387,7 +387,7 @@ void reflectorWatchConnectExceptionShouldUseExponentialBackoff()
       Thread thread = new Thread(reflectorRunnable::run);
       thread.setDaemon(true);
       thread.start();
-      assertThat(latch.await(2, TimeUnit.SECONDS)).isTrue();
+      assertThat(latch.await(5, TimeUnit.SECONDS)).isTrue();
     } finally {
       reflectorRunnable.stop();
     }