Perfprofd: Factor out threaded handler

To improve testability.

(cherry picked from commit b019ddc547f4491fee3ac95415767b02ae40edd1)

Bug: 73175642
Test: mmma system/extras/perfprofd
Test: perfprofd_test
Merged-In: I259b86b9ef7c8c7d8523f3875ce63c2e71e42543
Change-Id: I259b86b9ef7c8c7d8523f3875ce63c2e71e42543
3 files changed