[TextureMapperGL] Remove unused code for GL_TEXTURE_RECTANGLE_ARB
It was added by 105925@main (Bug 87738) for Qt-Mac port. But, no longer used.
Created attachment 460267 [details]
Committed r295587 (251592@main): <https://commits.webkit.org/251592@main>
All reviewed patches have been landed. Closing bug and clearing flags on attachment 460267 [details].