ActiveModeWarden: keep stopped ActiveModeManager instances for dumping

Keep the last 3 stopped instances of ClientModeManager/SoftApManager
in ActiveModeWarden for debugging purposes.

Bug: 160283853
Test: atest FrameworksWifiTests
Test: toggle wifi a few times, then run `adb shell dumpsys wifi`
    and verify output
Change-Id: I7ed47bc468bbb308ae45b4908e73a25485cce5a9
1 file changed
tree: 97a2ab28b4cc347aa4696e69984846e697af3db3
  1. apex/
  2. service/
  3. metrics_pdd_hook.py
  4. PREUPLOAD.cfg