selftests/bpf: Fix a test_verifier failure

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

$ ./test_verifier
...
#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
#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 <[e-mail]>
Signed-off-by: Yonghong Song <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Alexei Starovoitov <[e-mail]>

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

···
 	.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,
···
 	},
 	BPF_EXIT_INSN(),
 	},
-	.errstr = "unknown opcode d7",
+	.errstr = "unknown opcode df",
 	.result = REJECT,
 },
 {