builkite: log fatal signals

It can be useful to investigate bugs.

PiperOrigin-RevId: 521620352

.buildkite/hooks/post-command

@@ -54,6 +54,7 @@ rm -rf "${profile_output}"
 # Clean the bazel cache, if there's failure.
 if test "${BUILDKITE_COMMAND_EXIT_STATUS}" -ne "0"; then
   set -x
+  dmesg -kT | tail -n 50
   # LINT.IfChange
   runtime="buildkite_runtime_${BUILDKITE_BRANCH}-${BUILDKITE_BUILD_ID}"
   runtime="$(echo "$runtime" | sed -r 's~[^-_a-z0-9]+~_~g')"

.buildkite/hooks/pre-command

@@ -110,3 +110,5 @@ if test "${BUILDKITE_AGENT_META_DATA_QUEUE}" = "release"; then
   # Configure the Docker credential helper (to push images).
   gcloud auth configure-docker -q
 fi
+
+sudo sysctl -w kernel.print-fatal-signals=1