Use dumpAsText() to avoid an image result being generated
https://bugs.webkit.org/show_bug.cgi?id=71386

Reviewed by Tony Chang.

single-line-must-not-be-split-into-two-pages.html had been producing
a huge image result. What we need is a way by which we can generate a
DumpRenderTree result but do not generate an image even if
--pixel-test option is specified for ./Tools/Scripts/new-run-webkit-tests.
This patch realizes it using dumpAsText() and
window.internals.elementRenderTreeAsText.

* printing/single-line-must-not-be-split-into-two-pages.html: Used dumpAsText() and window.internals.elementRenderTreeAsText.
* platform/chromium-cg-mac-leopard/printing/single-line-must-not-be-split-into-two-pages-expected.png: Removed.
* platform/chromium-cg-mac-snowleopard/printing/single-line-must-not-be-split-into-two-pages-expected.png: Removed.
* platform/chromium-linux/printing/single-line-must-not-be-split-into-two-pages-expected.png: Removed.
* platform/chromium-mac-leopard/printing/single-line-must-not-be-split-into-two-pages-expected.png: Removed.
* platform/chromium-mac-snowleopard/printing/single-line-must-not-be-split-into-two-pages-expected.png: Removed.
* platform/chromium-win/printing/single-line-must-not-be-split-into-two-pages-expected.png: Removed.
* platform/chromium-win/printing/single-line-must-not-be-split-into-two-pages-expected.txt: Updated a test result.
* platform/mac/printing/single-line-must-not-be-split-into-two-pages-expected.txt: Ditto.


git-svn-id: svn://svn.chromium.org/blink/trunk@99772 bbb929c8-8fbe-4397-9dbb-9b2b20218538