ActivityManagerService: report current and max thrashing levels

Add thrashing and maxThrashing fields in LMK_KILL_OCCURRED report.

Bug: 194433891
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Change-Id: I016d95a9b2ba4b6f4ca814be1456cec59f4834da
Merged-In: I016d95a9b2ba4b6f4ca814be1456cec59f4834da