Make AnnotatedStackTraceElement class final

Also add nullability annotations.

Bug: 185153775
Test: m
Merged-In: I990b11921e56ba875508a4405adecd56ad24fba0
Change-Id: I990b11921e56ba875508a4405adecd56ad24fba0
(cherry picked from commit 8b1a09d27910d3e132124b886ab41a35d1552b36)
3 files changed