[infra] Fix reproduce command invoking run_fuzzer for a single testcase (google#4338). (google#4367)

* [infra] Fix reproduce command invoking run_fuzzer for a single testcase (google#4338).

* review feedback

* do not introduce new variable, rely on SKIP_SEED_CORPUS only

Author: Dor1s

infra/base-images/base-runner/reproduce

@@ -29,5 +29,6 @@ fi
 
 export RUN_FUZZER_MODE="interactive"
 export FUZZING_ENGINE="libfuzzer"
+export SKIP_SEED_CORPUS="1"
 
 run_fuzzer $FUZZER $@ $TESTCASE

infra/base-images/base-runner/run_fuzzer

@@ -67,6 +67,7 @@ rm -rf $CORPUS_DIR && mkdir $CORPUS_DIR
 rm -rf $FUZZER_OUT && mkdir $FUZZER_OUT
 
 SEED_CORPUS="${FUZZER}_seed_corpus.zip"
+
 if [ -f $SEED_CORPUS ] && [ -z ${SKIP_SEED_CORPUS:-} ]; then
   echo "Using seed corpus: $SEED_CORPUS"
   unzip -d ${CORPUS_DIR}/ $SEED_CORPUS > /dev/null
@@ -118,7 +119,11 @@ elif [[ "$FUZZING_ENGINE" = honggfuzz ]]; then
   # -n: number of fuzzing threads (and processes)
   CMD_LINE="$OUT/honggfuzz -n 1 --exit_upon_crash -R /tmp/${FUZZER}_honggfuzz.report -W $FUZZER_OUT -v -z -P -f \"$CORPUS_DIR\" $(get_dictionary) $* -- \"$OUT/$FUZZER\""
 else
-  CMD_LINE="$OUT/$FUZZER $FUZZER_ARGS $* $CORPUS_DIR"
+  CMD_LINE="$OUT/$FUZZER $FUZZER_ARGS $*"
+
+  if [ -z ${SKIP_SEED_CORPUS:-} ]; then
+    CMD_LINE="$CMD_LINE $CORPUS_DIR"
+  fi
 
   if [ ! -z $CUSTOM_LIBFUZZER_OPTIONS ]; then
     CMD_LINE="$CMD_LINE $CUSTOM_LIBFUZZER_OPTIONS"