Display bpf-tools version in cargo-build-bpf version string (#22061)

* Display bpf-tools version in cargo-build-bpf version string

* Print cargo-build-bpf version in CI for reference in stable-bpf jobs

ci/test-stable.sh

@@ -65,6 +65,9 @@ test-stable-bpf)
     fi
   done
 
+  # bpf-tools version
+  "$cargo_build_bpf" -V
+
   # BPF program instruction count assertion
   bpf_target_path=programs/bpf/target
   _ "$cargo" stable test \