Remove more cruft now that HTMLIsIndexElement is gone

Remove more cruft now that HTMLIsIndexElement is gone
https://bugs.webkit.org/show_bug.cgi?id=77887

Reviewed by Darin Adler.

Just removing dead code, thus no tests.
There is likely more to remove after this.

* CMakeLists.txt:
* GNUmakefile.list.am:
* Target.pri:
* WebCore.gypi:
* WebCore.vcproj/WebCore.vcproj:
* WebCore.xcodeproj/project.pbxproj:
* html/HTMLInputElement.cpp:
* html/HTMLInputElement.h:
(HTMLInputElement):
* html/InputType.cpp:
(WebCore::createInputTypeFactoryMap):
* html/InputType.h:
(InputTypeNames):
* html/IsIndexInputType.cpp: Removed.
* html/IsIndexInputType.h: Removed.
* rendering/HitTestResult.cpp:
(WebCore::HitTestResult::isContentEditable):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@107175 268f45cc-cd09-0410-ab3c-d52691b4dbfc