Issue with typeof checks handling

[praj-github]

Bug report or feature request?: Bug report

ES5 or ES6+ input?: ES5+

Uglify version (uglifyjs -V): uglify-js 2.8.12

JavaScript input

var xmlHttpReq = new ActiveXObject("MSXML2.XMLHTTP.6.0");
if (typeof xmlHttpReq.setRequestHeader != "undefined") {
console.log("works")
}

Testing this on IE11. This code prints "works".

The uglifyjs CLI command executed or minify() options used.

uglifyjs --compress --mangle --ie8

JavaScript output or error produced.
JS output:
void 0!==new ActiveXObject("MSXML2.XMLHTTP.6.0").setRequestHeader&&console.log("works");

Output error when this was run on IE11:
"Wrong number of arguments or invalid property assignment"

[alexlamsl]

Not reproducible in latest version of uglify-js

[praj-github]

Thanks a lot for your response!