fix corner case in inline (#5415)

fixes #5414

lib/compress.js

@@ -13382,7 +13382,7 @@ Compressor.prototype.compress = function(node) {
             });
             var body = [];
             fn.variables.each(function(def, name) {
-                if (name == "arguments") return;
+                if (!arrow && name == "arguments" && def.orig.length == 1) return;
                 names.set(name, true);
                 scope.enclosed.push(def);
                 scope.variables.set(name, def);