selftests/bpf: Add tests for BPF_DIV analysis

Now BPF_DIV has value tracking support via interval and tnum analysis.
This patch adds selftests to cover various cases of signed and
unsigned division operations, including edge cases like division by
zero and signed division overflow.

Specifically, these selftests are based on dead code elimination: If
the BPF verifier can precisely analyze the result of a division
operation, it can prune the path that leads to an error (here we use
invalid memory access as the error case), allowing the program to pass
verification.

Co-developed-by: Shenghao Yuan <shenghaoyuan0928@163.com>
Signed-off-by: Shenghao Yuan <shenghaoyuan0928@163.com>
Co-developed-by: Tianci Cao <ziye@zju.edu.cn>
Signed-off-by: Tianci Cao <ziye@zju.edu.cn>
Signed-off-by: Yazhou Tang <tangyazhou518@outlook.com>

Author: ADSWT518

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

@@ -33,6 +33,7 @@
 #include "verifier_direct_packet_access.skel.h"
 #include "verifier_direct_stack_access_wraparound.skel.h"
 #include "verifier_div0.skel.h"
+#include "verifier_div_bounds.skel.h"
 #include "verifier_div_overflow.skel.h"
 #include "verifier_global_subprogs.skel.h"
 #include "verifier_global_ptr_args.skel.h"
@@ -174,6 +175,7 @@ void test_verifier_d_path(void)               { RUN(verifier_d_path); }
 void test_verifier_direct_packet_access(void) { RUN(verifier_direct_packet_access); }
 void test_verifier_direct_stack_access_wraparound(void) { RUN(verifier_direct_stack_access_wraparound); }
 void test_verifier_div0(void)                 { RUN(verifier_div0); }
+void test_verifier_div_bounds(void)           { RUN(verifier_div_bounds); }
 void test_verifier_div_overflow(void)         { RUN(verifier_div_overflow); }
 void test_verifier_global_subprogs(void)      { RUN(verifier_global_subprogs); }
 void test_verifier_global_ptr_args(void)      { RUN(verifier_global_ptr_args); }