Do not use pkg_tars again in skia_app_container if run_commands_root or
run_commands_skia is specified

This bug had 2 effects:
* Any changes to directories in pkg_tars by run_commands_root and
  run_commands_skia were overriden.
* Files/directories moved out of pkg_tars still existed causing slow
  builds of certain apps.

Bug: skia:12816
Change-Id: I2d9b7bff938f6f3bc3233aea9b28b81186509bc2
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/494856
Reviewed-by: Leandro Lovisolo <lovisolo@google.com>
Commit-Queue: Ravi Mistry <rmistry@google.com>
diff --git a/bazel/skia_app_container.bzl b/bazel/skia_app_container.bzl
index b9cdc64..da7c928 100644
--- a/bazel/skia_app_container.bzl
+++ b/bazel/skia_app_container.bzl
@@ -199,7 +199,6 @@
             base = image_name,
             entrypoint = [entrypoint],
             stamp = True,
-            tars = pkg_tars,
             user = "skia",
             tags = ["manual"],  # Exclude it from wildcard queries, e.g. "bazel build //...".
             env = env,