Skip BpfExistenceTest#TestPrograms on BPF unsupported device

BPF is supported after kernel 4.9. Skip the test on BPF
unsupported device. Ex: walleye.

Bug: 219696135
Test: atest bpf_existence_test on walleye
Change-Id: I583a858587c0501582c9e77c8b584b3136312cd5

tests/mts/Android.bp

@@ -27,6 +27,9 @@ cc_test {
         "connectivity-mainline-presubmit-cc-defaults",
     ],
     require_root: true,
+    header_libs: [
+        "bpf_headers",
+    ],
     static_libs: [
         "libbase",
         "libmodules-utils-build",

tests/mts/bpf_existence_test.cpp

@@ -23,6 +23,7 @@
 #include <android/api-level.h>
 #include <android-base/properties.h>
 #include <android-modules-utils/sdk_level.h>
+#include <bpf/BpfUtils.h>
 
 #include <gtest/gtest.h>
 
@@ -151,6 +152,8 @@ void checkFiles() {
 }
 
 TEST_F(BpfExistenceTest, TestPrograms) {
+    SKIP_IF_BPF_NOT_SUPPORTED;
+
     // Pre-flight check to ensure test has been updated.
     uint64_t buildVersionSdk = android_get_device_api_level();
     ASSERT_NE(0, buildVersionSdk) << "Unable to determine device SDK version";