[native] Update threadStore with threadStoreOps in fixUnreadActiveThread

Summary:
Based on months with assertThreadStoreThreadsAreEqual enabled on staff builds, I think it's safe to conclude that processing the threadStore with the threadStoreOps leads to an equivalent result. There's no need to create an updatedThreadStore twice, so we're removing the non-ops approach.

Depends on D4193

Test Plan: assertThreadStoreThreadsAreEqual hasn't flagged anything since it's been included in staff builds

Reviewers: def-au1t, palys-swm

Reviewed By: palys-swm

Subscribers: ashoat, Adrian, yayabosh

Differential Revision: https://phab.comm.dev/D4194