selftests: bpf: break up the rest of test_verifier

Break up the rest of test_verifier tests into separate
files.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/verifier/xdp.c

@@ -0,0 +1,14 @@
+{
+	"XDP, using ifindex from netdev",
+	.insns = {
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
+		    offsetof(struct xdp_md, ingress_ifindex)),
+	BPF_JMP_IMM(BPF_JLT, BPF_REG_2, 1, 1),
+	BPF_MOV64_IMM(BPF_REG_0, 1),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.prog_type = BPF_PROG_TYPE_XDP,
+	.retval = 1,
+},