buildkite: Run bazel with the remote cache

PiperOrigin-RevId: 572991580

.buildkite/hooks/pre-command

@@ -1,5 +1,7 @@
 set -euo pipefail
 
+export BAZEL_REMOTE_CACHE="--remote_cache=https://storage.googleapis.com/gvisor-buildkite-bazel-cache --google_default_credentials"
+
 if POSIXLY_CORRECT=true df --local --output=pcent,ipcent,target | grep -vE '/snap/' | grep -qE '9[4-9]%|100%'; then
   echo "Disk usage has reached critical level, node is bad." >&2
   echo "Automated monitoring should recycle this node soon." >&2

tools/bazel.mk

@@ -73,11 +73,12 @@ PRE_BAZEL_INIT ?=
 ##
 ##     STARTUP_OPTIONS - Startup options passed to Bazel.
 ##
-STARTUP_OPTIONS :=
-BAZEL_OPTIONS   ?=
-BAZEL           := bazel $(STARTUP_OPTIONS)
-BASE_OPTIONS    := --color=no --curses=no
-TEST_OPTIONS += $(BASE_OPTIONS) \
+STARTUP_OPTIONS    :=
+BAZEL_OPTIONS      ?=
+BAZEL_REMOTE_CACHE ?=
+BAZEL              := bazel $(STARTUP_OPTIONS)
+BASE_OPTIONS       := --color=no --curses=no $(BAZEL_REMOTE_CACHE)
+TEST_OPTIONS       += $(BASE_OPTIONS) \
   --test_output=errors \
   --keep_going \
   --verbose_failures=true \