Make encoding-labels test easier to debug

Make encoding-labels test easier to debug

It's hard to find out which label failed for a given encoding.
Revise encoding-labels.html to print out {encoding name, label) pair
instead of just 'encoding name' for each test run.

BUG=412053
TEST=fast/encoding/encoding-labels.html

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=182685

[jungshik at Google, 2014-09-25 09:00:02]

jshin@chromium.org changed reviewers:
+ jsbell@chromium.org

[jungshik at Google, 2014-09-25 09:00:03]

Hi Joshua, can you take a look? 

While working on the bug in BUG field, encoding-labels test failed for
iso-8859-8-i, but I had to test 3 labels one-by-one in JS console to find out
which one failed. This change makes it easy to find that out.

[jsbell, 2014-09-25 14:15:15]

lgtm

[jsbell, 2014-09-25 14:15:23]

The CQ bit was checked by jsbell@chromium.org

[commit-bot: I haz the power, 2014-09-25 14:15:43]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/599403002/60001

[commit-bot: I haz the power, 2014-09-25 15:55:12]

Committed patchset #4 (id:60001) as 182685