selftests/bpf: Fix a test_verifier failure

The following test_verifier subtest failed due to
new encoding for BSWAP.

  $ ./test_verifier
  ...
  torvalds#99/u invalid 64-bit BPF_END FAIL
  Unexpected success to load!
  verification time 215 usec
  stack depth 0
  processed 3 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0
  torvalds#99/p invalid 64-bit BPF_END FAIL
  Unexpected success to load!
  verification time 198 usec
  stack depth 0
  processed 3 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0

Tighten the test so it still reports a failure.

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230728011244.3717464-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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

@@ -176,19 +176,19 @@
 	.retval = 1,
 },
 {
-	"invalid 64-bit BPF_END",
+	"invalid 64-bit BPF_END with BPF_TO_BE",
 	.insns = {
 	BPF_MOV32_IMM(BPF_REG_0, 0),
 	{
-		.code  = BPF_ALU64 | BPF_END | BPF_TO_LE,
+		.code  = BPF_ALU64 | BPF_END | BPF_TO_BE,
 		.dst_reg = BPF_REG_0,
 		.src_reg = 0,
 		.off   = 0,
 		.imm   = 32,
 	},
 	BPF_EXIT_INSN(),
 	},
-	.errstr = "unknown opcode d7",
+	.errstr = "unknown opcode df",
 	.result = REJECT,
 },
 {