[CMake] Add error checking to WEBKIT_OPTION_DEFAULT_PORT_VALUE et. al.

[CMake] Add error checking to WEBKIT_OPTION_DEFAULT_PORT_VALUE et. al.
https://bugs.webkit.org/show_bug.cgi?id=144069

Reviewed by Martin Robinson.

* Source/cmake/OptionsWin.cmake:
Do not set options that no longer exist.
* Source/cmake/WebKitFeatures.cmake:
Add error checking to ensure that option names passed to WEBKIT_OPTION_DEFAULT_PORT_VALUE,
WEBKIT_OPTION_CONFLICT, and WEBKIT_OPTION_DEPEND are actually valid options that have been
previously-defined. Also, add ENABLE_SVG_OTF_CONVERTER build option, defaulted to off since
no CMake port was using it.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@194456 268f45cc-cd09-0410-ab3c-d52691b4dbfc