Perf: faster is-domain-loose check

Build/build-reject-domainset.js

@@ -45,7 +45,10 @@ const filterRuleWhitelistDomainSets = new Set(PREDEFINED_WHITELIST);
     if (Array.isArray(input) && input.length === 2) {
       return processFilterRules(input[0], input[1]);
     }
-  }))).forEach(({ white, black }) => {
+  }))).forEach(({ white, black, foundDebugDomain }) => {
+    if (foundDebugDomain) {
+      process.exit(1);
+    };
     white.forEach(i => filterRuleWhitelistDomainSets.add(i));
     black.forEach(i => domainSets.add(i));
   });