By code inspection I found that loadWithNewGlobal uses wrong global instance (new global created rather than caller's global) to wrap input arguments.

Test:

loadWithNewGlobal({
    name: "test",
    script: "arguments[0]();"
}, func);

function func() {
    try {
        foo;
    } catch (e) {
        if (! (e instanceof ReferenceError)) {
            print("FAILED: expected ReferenceError!");
        }
    }
}


Should not print "FAILED..."