ANDROID: vendor hooks: skip mem reclaim throttle to speed up mem alloc

1.Allowing certain important threads to skip waiting and direct mem
reclaim, speeding up mem allocation for critical processes.

2.Correcting the statistical count error for PGSCAN_DIRECT_THROTTLE.

Bug: 335586788

Change-Id: I85bbf895d678eb3f5269d3e7a7b3b58e0ebd90fe
Signed-off-by: Lei Liu <liulei.rjpt@vivo.corp-partner.google.com>