Revert^2 "lshal: use std::async"

This reverts commit 2cfbc514764472becab46b41ebe0323a68369cad.

Reason for revert: reapply change

Bug: 323268003
Bug: 311143089
Test: See next CL
Change-Id: I392eca8f3368c1d74b4de37d5f49663d3ddbf7e0
3 files changed