Reduce the preparation work on cold project for build cleaning

We don't really need to build everything, just loading the repos
and building the genrules.

.github/bin/run-build-cleaner.sh

diff --git a/.github/bin/run-build-cleaner.sh b/.github/bin/run-build-cleaner.sh
index d5b03f7..e372646 100755
--- a/.github/bin/run-build-cleaner.sh
+++ b/.github/bin/run-build-cleaner.sh
@@ -17,19 +17,25 @@
 set -e
 
 BANT=$($(dirname $0)/get-bant-path.sh)
+BAZEL=bazel
 
 # Run build so that we have all dependencies downloaded and genrules
 # materialized.
-bazel build -k --remote_download_outputs=all ...
+for f in abseil-cpp nlohmann_json protobuf re2 rules_flex zlib googletest ; do
+  "${BAZEL}" fetch --repo "@$f" > /dev/null 2>&1
+done
 
-if "${BANT}" -q dwyu ... ; then
+"${BAZEL}" build -k --remote_download_outputs=all \
+           $(${BANT} genrule-outputs ... -c2) > /dev/null 2>&1
+
+if "${BANT}" dwyu $@; then
   echo "Dependencies ok." >&2
 else
   cat >&2 <<EOF
 
 Build dependency issues found, the following one-liner will fix it. Amend PR.
 
-source <(.github/bin/run-build-cleaner.sh)
+source <(.github/bin/run-build-cleaner.sh $@)
 EOF
   exit 1
 fi

.github/workflows/verible-ci.yml

diff --git a/.github/workflows/verible-ci.yml b/.github/workflows/verible-ci.yml
index 802a7a3..31a7c21 100644
--- a/.github/workflows/verible-ci.yml
+++ b/.github/workflows/verible-ci.yml
@@ -51,7 +51,7 @@
         echo "--- check formatting ---"
         CLANG_FORMAT=clang-format-19 ./.github/bin/run-format.sh --show-diff
         echo "--- check build dependencies ---"
-        ./.github/bin/run-build-cleaner.sh
+        ./.github/bin/run-build-cleaner.sh ...
         echo "--- check potential problems ---"
         ./.github/bin/check-potential-problems.sh