Fix longstanding 0B in heap tile

Also adds the number of views and ExpandableNotificationRows
to the subtext. The former is likely to be in the 1000s for
a healthy SystemUI process; the latter should be roughly
equivalent to the number of notifications (otherwise there
is a leak).

Fixes: 159917121
Test: make, pull down QS, examine tile
Change-Id: I97b17fb8e991264db612b8a6689051b8d83b4222