Call FallbackRecentsView#init() before setContentView()

* Init sets mSplitSelectStateController which RecentsView
then uses in onAttachedToWindow(). That needs to be set
before it gets attached to the window, which happens in
RecentsActivity#setContentView()

Fixes: 332643607
Test: Only presubmit, issue not reproducible
Flag: EXEMPT bugfix
Change-Id: Icc555cad17b734e2a9c035991c19bbdc6b02de5d