Remove unnecessary `removeFromApp` parameter

Always remove the activity from its process while calling
#destroyImmediately() and remove the unnecessary removeFromApp
parameter since the value is always true from all callers.

Bug: 161447610
Test: atest ActivityRecordTests
Change-Id: I5333ea7d3c07bddd29e1070ae373c0b24a281d9c
7 files changed