[PR] Avoid infinite loop in DeltaManager with invalid batch si ze [tomcat]

lihongyi87 opened a new pull request, #1042:
URL: https://github.com/apache/tomcat/pull/1042

   ## Problem
   
   When `sendAllSessions` is `false` and `sendAllSessionsSize` is configured to zero or a negative value, the batch loop in `handleGET_ALL_SESSIONS` never terminates:
   
   ```java
   for (int i = 0; i < currentSessions.length; i += getSendAllSessionsSize()) {
   ```
   
   - With `sendAllSessionsSize == 0`: `i` never advances, so the loop runs indefinitely, sending empty session arrays and sleeping on each iteration. This blocks the cluster receiver thread on the master node and prevents `EVT_ALL_SESSION_TRANSFERCOMPLETE` from ever being sent.
   - With `sendAllSessionsSize < 0`: `i` decreases, and `new Session[len]` throws `NegativeArraySizeException`.
   
   The `setSendAllSessionsSize` setter performs no validation, and the documentation (`cluster-manager.xml`) does not state a minimum value.
   
   ## Fix
   
   When `sendAllSessionsSize` is not positive, fall back to sending all sessions in a single batch (the same behaviour as `sendAllSessions == true`):
   
   ```java
   if (isSendAllSessions() || getSendAllSessionsSize() <= 0) {
   ```
   
   This is a one-line change at the point of use, keeping the setter unmodified for consistency with the rest of `DeltaManager`.


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