veristat, kernel-test: fix vmlinuz search

By using sparse checkout in kernel-test and veristat jobs we can save
about 1.5 minute of runtime on each job. Job invoking
libbpf/ci/run-vmtest action do not need access to the full kernel
source tree.

However, this requires an adjustment to the list of the artifacts
collected by kernel build. VMLINUZ might be search via `make
image_name`, which requires makefiles and other scripts to be
accessible.

Example of a failure:
https://github.com/kernel-patches/bpf/actions/runs/12204941090/job/34051427386

Set ARCHIVE_MAKE_HELPERS flag for libbpf/ci/tar-artifacts action to
true in kernel-build.

Also, add check for vars.AWS_REGION before executing veristat-meta.

Signed-off-by: Ihor Solodrai <[email protected]>

.github/workflows/kernel-build-test.yml

@@ -113,7 +113,8 @@ jobs:
       runs_on: ${{ inputs.runs_on }}
 
   veristat-meta:
-    if: ${{ inputs.run_veristat && github.repository_owner == 'kernel-patches' }}
+    # Check for vars.AWS_REGION is necessary to skip this job in case of a PR from a fork.
+    if: ${{ inputs.run_veristat && github.repository_owner == 'kernel-patches' && vars.AWS_REGION }}
     uses: ./.github/workflows/veristat-meta.yml
     needs: [build]
     permissions:

.github/workflows/kernel-build.yml

@@ -147,7 +147,7 @@ jobs:
         uses: libbpf/ci/tar-artifacts@v2
         env:
           ARCHIVE_BPF_SELFTESTS: 'true'
-          ARCHIVE_MAKE_HELPERS: ${{ github.repository != 'kernel-patches/bpf' && 'true' || '' }}
+          ARCHIVE_MAKE_HELPERS: 'true'
           ARCHIVE_SCHED_EXT_SELFTESTS: ${{ env.BUILD_SCHED_EXT_SELFTESTS }}
         with:
           arch: ${{ inputs.arch }}

.github/workflows/kernel-test.yml

@@ -50,6 +50,10 @@ jobs:
       DENYLIST_FILE: /tmp/denylist
     steps:
       - uses: actions/checkout@v4
+        with:
+          sparse-checkout: |
+            .github
+            ci
 
       - uses: actions/download-artifact@v4
         with: