The test input-paste-undo.html needs update to work properly

The test input-paste-undo.html needs update to work properly
https://bugs.webkit.org/show_bug.cgi?id=71091

Reviewed by David Kilzer.

Update the test to select the text that needs to be copied
so that it effectively go in the pasteboard on execCommand.

The test now dumps result as text, testing if the height does not
change with the form edition.

* fast/forms/input-paste-undo-expected.txt: Added.
* fast/forms/input-paste-undo.html:
* platform/chromium-linux/fast/forms/input-paste-undo-expected.png: Removed.
* platform/chromium-mac-leopard/fast/forms/input-paste-undo-expected.png: Removed.
* platform/chromium-mac/fast/forms/input-paste-undo-expected.png: Removed.
* platform/chromium-win/fast/forms/input-paste-undo-expected.png: Removed.
* platform/chromium-win/fast/forms/input-paste-undo-expected.txt: Removed.
* platform/efl/fast/forms/input-paste-undo-expected.txt: Removed.
* platform/gtk/fast/forms/input-paste-undo-expected.png: Removed.
* platform/gtk/fast/forms/input-paste-undo-expected.txt: Removed.
* platform/mac-leopard/fast/forms/input-paste-undo-expected.png: Removed.
* platform/mac/fast/forms/input-paste-undo-expected.png: Removed.
* platform/mac/fast/forms/input-paste-undo-expected.txt: Removed.
* platform/qt/fast/forms/input-paste-undo-expected.txt: Removed.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@98886 268f45cc-cd09-0410-ab3c-d52691b4dbfc