TextCodecICU::encode turns the whole string as yen signs if there is any backslash in it
https://bugs.webkit.org/show_bug.cgi?id=133678

Patch by Youenn Fablet <youenn.fablet@crf.canon.fr> on 2014-06-29
Reviewed by Alexey Proskuryakov.

Source/WebCore:
Test: fast/encoding/backslash-encoding-jp.html

* platform/text/TextCodecICU.cpp:
(WebCore::TextCodecICU::encode): fixed the copy of characters other than backslash.

LayoutTests:
* fast/encoding/backslash-encoding-jp-expected.txt: Added.
* fast/encoding/backslash-encoding-jp.html: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@170573 268f45cc-cd09-0410-ab3c-d52691b4dbfc