Test failure with uglifyjs 2.8

[remicollet]

From Fedora QA
https://apps.fedoraproject.org/koschei/package/php-Assetic?collection=f28

Everythin ok with 2.7
Test failure with 2.8

There was 1 failure:
1) Assetic\Test\Filter\UglifyJs2FilterTest::testCompress
Failed asserting that '"undefined"==typeof DEBUG&&(DEBUG=!0),"undefined"==typeof FOO&&(FOO=1),function(){function bar(foo){return var2.push(foo),foo}var bar=(new Array(FOO,2,3,4),Array(a,b,c)),var2=(new Array(5),new Array(a));(function(var1){DEBUG&&console.log("hellow world")})("abc123"),bar("abc123")}();' contains "var foo".
/builddir/build/BUILD/assetic-e911c437dbdf006a8f62c2f59b15b2d69a5e0aa1/tests/Assetic/Test/Filter/UglifyJs2FilterTest.php:96