Revert "api: artifacts: Move BundleTestUpdatePayloads into chroot"

This reverts commit cb454e0444735d23845f5d092b49c6a6090534bc.

Reason for revert: causing BundleTestUpdatePayloads failures for
minios boards

Original change's description:
> api: artifacts: Move BundleTestUpdatePayloads into chroot
>
> api/gen changes to pull in:
>
>   artifacts: Move BundleTestUpdatePayloads into chroot
>
> We want to run this endpoint inside the chroot, because it forks out to
> many programs that need to enter the chroot, and that's a bit unwieldy
> to do properly (i.e., plumb all the right chroot arguments) in some
> cases.
>
> The router and field_handler layers do most of the artifact (ResultPath
> and Path) translation and copying for us, so we only have to do a few
> things to place artifacts into the in-chroot tmp directory, instead of
> directly into the |result_path|.
>
> I don't convert all the other "legacy" bundle endpoints here, since
> AFAICT, they handle chroot entry properly today.
>
> BUG=b:187787264
> TEST=./run_tests
> TEST=manual build_api execution
>
> Cq-Depend: chromium:4703006
> Change-Id: I60d106bbce1e324850aec4d4fc69fdc054b5c3e2
> Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/4701636
> Reviewed-by: Alex Klein <saklein@chromium.org>
> Tested-by: Brian Norris <briannorris@chromium.org>
> Commit-Queue: Brian Norris <briannorris@chromium.org>

BUG=b:187787264

Change-Id: Ibdc9b82f78f3ff967f02b86165d451e16601da05
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/4717971
Auto-Submit: Brian Norris <briannorris@chromium.org>
Reviewed-by: Yunfan Chen <yunfanc@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Owners-Override: Yunfan Chen <yunfanc@chromium.org>
Commit-Queue: Yunfan Chen <yunfanc@chromium.org>
diff --git a/api/controller/artifacts_unittest.py b/api/controller/artifacts_unittest.py
index 57e72df..9630a6d 100644
--- a/api/controller/artifacts_unittest.py
+++ b/api/controller/artifacts_unittest.py
@@ -692,19 +692,15 @@
         )
 
         actual = [
-            os.path.basename(artifact.artifact_path.path)
+            os.path.relpath(artifact.artifact_path.path, self.archive_root)
             for artifact in self.output_proto.artifacts
         ]
         expected = ["payload1.bin", "payload2.bin"]
         self.assertCountEqual(actual, expected)
 
         actual = [
-            os.path.basename(path)
-            for path in osutils.DirectoryIterator(
-                os.path.dirname(
-                    self.output_proto.artifacts[0].artifact_path.path
-                )
-            )
+            os.path.relpath(path, self.archive_root)
+            for path in osutils.DirectoryIterator(self.archive_root)
         ]
         self.assertCountEqual(actual, expected)