libbpf-compat: skip tests that fail on 5.18

5.18 added two new BTF kinds TYPE_TAG and DECL_TAG which we
don't support at the moment.

See #713

elf_reader_test.go

@@ -690,6 +690,9 @@ func TestLibBPFCompat(t *testing.T) {
 		case "bloom_filter_map.o", "bloom_filter_map.linked3.o",
 			"bloom_filter_bench.o", "bloom_filter_bench.linked3.o":
 			t.Skip("Skipping due to missing MapExtra field in MapSpec")
+		case "btf_type_tag.o", "btf_type_tag.linked3.o", "test_btf_decl_tag.o",
+			"test_btf_decl_tag.linked3.o":
+			t.Skip("Skipping due to missing support for BTF_KIND_TYPE_TAG and BTF_KIND_DECL_TAG")
 		}
 
 		t.Parallel()