ANDROID: add hook for send signal debug

The hook is added to get the system memory states at send_signal time.
It is used for problem analysis. Additionally adjust the memory
reclaim strategy to improve the system's memory states.

Bug: 385881042
Bug: 383646535
Change-Id: Ia2cec73e4588f4dd2f07dd47eb3375e19df894f5
Signed-off-by: Justin Jiang <justinjiang@vivo.corp-partner.google.com>
(cherry picked from commit 3bdcda6c)