Remove the uses of QuicheStrCat() outside of QUICHE.

Change-Id: I3d4c8ff60b76182200f826a040d018edc61dc869
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2579827


Reviewed-by: David Schinazi <dschinazi@chromium.org>
Reviewed-by: Yutaka Hirano <yhirano@chromium.org>
Commit-Queue: Victor Vasiliev <vasilvv@chromium.org>
Cr-Commit-Position: refs/heads/master@{#835317}