Optimization: Make clean-up of DeviceTempFile() async
Optimization: Make clean-up of DeviceTempFile() async

Brings the no-op case of managed_install.py from 9s -> 8.5s
chrome_modern_with_splits_managed when adb is forwarded over ssh.

Uses threading, but since DeviceTempFile() uses adb_wrapper rather than
device_utils, there is no state being mutated by the call.

BUG=520082

Review URL: https://codereview.chromium.org/1283323008

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#345137}

CapOM/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend