[ci, bazel] Bring englishbreakfast systemtest under Bazel control

Signed-off-by: Miles Dai <milesdai@google.com>
diff --git a/ci/scripts/build-chip-verilator.sh b/ci/scripts/build-chip-verilator.sh
index 3fffd05..654d183 100755
--- a/ci/scripts/build-chip-verilator.sh
+++ b/ci/scripts/build-chip-verilator.sh
@@ -21,11 +21,14 @@
         fileset=fileset_top
         fusesoc_core=lowrisc:dv:chip_verilator_sim
         vname=Vchip_sim_tb
+        verilator_options="--threads 4"
         ;;
     englishbreakfast)
         fileset=fileset_topgen
         fusesoc_core=lowrisc:systems:chip_englishbreakfast_verilator
         vname=Vchip_englishbreakfast_verilator
+        # Englishbreakfast on CI runs on a 2-core CPU
+        verilator_options="--threads 2"
 
         util/topgen-fusesoc.py --files-root=. --topname=top_englishbreakfast
         ;;
@@ -48,7 +51,7 @@
   run --flag=$fileset --target=sim --setup --build \
   --build-root="$OBJ_DIR/hw" \
   $fusesoc_core \
-  --verilator_options="--threads 4"
+  --verilator_options="${verilator_options}"
 
 cp "$OBJ_DIR/hw/sim-verilator/${vname}" \
    "$BIN_DIR/hw/top_${tl}/Vchip_${tl}_verilator"