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
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:aeecb1e8a5cabe9fc58af69f7b47764a96a08d76)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:eac1d34438209f266212b1bbe8c9704c2947dbcd)
Merged-In: Icc555cad17b734e2a9c035991c19bbdc6b02de5d
Change-Id: Icc555cad17b734e2a9c035991c19bbdc6b02de5d