Keep oom_adj score low for top started EJs.

Treat EJs similar to FGS by keeping the oom_adj score low after an app
leaves the TOP state for a short period of time. Only do this special
case for EJs started while the app was TOP.

Bug: 223437753
Test: Android builds
Change-Id: Iba097c82080444996d9ff752f6fc963c56319bdb