multiline string support

[eromoe]

Because I need use evaluateJavaScript which only accept string, but my script has multiline.

In es6 , node 4, below code work:

var str = `Some 
    String 
    Here`;

But phantomjs only support:

var str = "Some \
    String \
    Here";

[ariya]

Please track ES6 support in #14506. Thank you!