Reland "Fix //testing import lint issues"

This is a reland of commit a418670f47e2a8bb3a2ce69e990203eb69b5225f

Changes from original CL:
* Fixed run_variations_smoke_test.py being unable to import
  from //build

Original change's description:
> Fix //testing import lint issues
>
> Removes the import-related entries from //testing's pylintrc file and
> fixes resulting lint errors.
>
> Bug: 353942917
> Change-Id: Ie3b3dba795e0806631c37243a3b4f480a4215a6e
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5737567
> Auto-Submit: Brian Sheedy <[email protected]>
> Commit-Queue: Brian Sheedy <[email protected]>
> Reviewed-by: Ben Pastene <[email protected]>
> Cr-Commit-Position: refs/heads/main@{#1337485}

Bug: 353942917
Change-Id: Id9495cb75529fcc76037070abb4837d45f94210f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5766912
Reviewed-by: Ben Pastene <[email protected]>
Commit-Queue: Ben Pastene <[email protected]>
Auto-Submit: Brian Sheedy <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1338093}
NOKEYCHECK=True
GitOrigin-RevId: c0021a86cb08d9c5fa63382560506a9967a056a0
10 files changed