ci: switch to libbpf/ci/build-selftests action

Signed-off-by: Ihor Solodrai <ihor.solodrai@pm.me>

ci/vmtest/prepare-selftests-build-5.5.0.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+set -euo pipefail
+
+cd "${SELFTESTS_BPF}"
+printf "all:\n\ttouch bpf_testmod.ko\n\nclean:\n" > bpf_testmod/Makefile
+printf "all:\n\ttouch bpf_test_no_cfi.ko\n\nclean:\n" > bpf_test_no_cfi/Makefile
+

ci/vmtest/prepare-selftests-run.sh

@@ -0,0 +1,41 @@
+#!/bin/bash
+
+set -euo pipefail
+
+function append_into() {
+    local out="$1"
+    shift
+    local files=("$@")
+    echo -n > "$out"
+    for file in "${files[@]}"; do
+        cat "$file" >> "$out" || true
+    done
+}
+
+allowlists=(
+    "${SELFTESTS_BPF}/ALLOWLIST"
+    "${SELFTESTS_BPF}/ALLOWLIST.${ARCH}"
+    "${VMTEST_CONFIGS}/ALLOWLIST"
+    "${VMTEST_CONFIGS}/ALLOWLIST-${KERNEL}"
+    "${VMTEST_CONFIGS}/ALLOWLIST-${KERNEL}.${ARCH}"
+)
+
+append_into "${ALLOWLIST_FILE}" "${allowlists[@]}"
+
+denylists=(
+    "${SELFTESTS_BPF}/DENYLIST"
+    "${SELFTESTS_BPF}/DENYLIST.${ARCH}"
+    "${VMTEST_CONFIGS}/DENYLIST"
+    "${VMTEST_CONFIGS}/DENYLIST-${KERNEL}"
+    "${VMTEST_CONFIGS}/DENYLIST-${KERNEL}.${ARCH}"
+)
+
+append_into "${DENYLIST_FILE}" "${denylists[@]}"
+
+if [[ "${KERNEL}" == "5.5.0" ]]; then
+    echo "KERNEL_TEST=test_progs test_progs_no_alu32" >> $GITHUB_ENV
+fi
+
+mkdir "${GITHUB_WORKSPACE}/selftests"
+cp -R "${SELFTESTS_BPF}" "${GITHUB_WORKSPACE}/selftests"
+