Fix FAB setBackgroundTintList on L+

Caused by LayerDrawable caching its isStateful
value, meaning that if our shape drawable is not
stateful at instantiation (which is the default),
and a stateful tint is later set, it doesn't work
across state changes.

Test: included
BUG: 32785441

Change-Id: Id81951c5312785821f577c04ff657042edd899ed
7 files changed