bug: Fixing bash error (#4624)

Author: maddeleine

tests/fuzz/runFuzzTest.sh

@@ -203,7 +203,7 @@ then
             COVERAGE_FAILURE_ALLOWED=1
         fi
 
-        if [ "$FEATURE_COVERAGE" -lt $MIN_FEATURES_COVERED && COVERAGE_FAILURE_ALLOWED -eq 0 ]; then
+        if [[ "$FEATURE_COVERAGE" -lt $MIN_FEATURES_COVERED && COVERAGE_FAILURE_ALLOWED -eq 0 ]]; then
             printf "\033[31;1mERROR!\033[0m ${TEST_NAME} only covers ${FEATURE_COVERAGE} features, which is below ${MIN_FEATURES_COVERED}! This may be due to missing corpus files or a bug.\n"
             exit -1;
         fi