Parametrize run-with-jhbuild and update-webkitgtk-libs with platform --gtk/--efl

Parametrize run-with-jhbuild and update-webkitgtk-libs with platform --gtk/--efl
https://bugs.webkit.org/show_bug.cgi?id=79673

Preparatory work for bringing jhbuild enabled build to EFL port.

Patch by Dominik Röttsches <dominik.rottsches@linux.intel.com> on 2012-03-15
Reviewed by Philippe Normand.

* Scripts/update-webkit-libs-jhbuild: Copied from Tools/Scripts/update-webkitgtk-libs.
* Scripts/update-webkitgtk-libs:
* gtk/run-with-jhbuild:
* jhbuild/jhbuild-wrapper: Copied from Tools/gtk/run-with-jhbuild.
(top_level_path):
(jhbuild_installed):
(jhbuild_cloned):
(jhbuild_at_expected_revision):
(update_jhbuild):
(clone_jhbuild):
(install_jhbuild):
(update_webkit_libs_jhbuild):
(determine_platform):
(ensure_jhbuild):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@110846 268f45cc-cd09-0410-ab3c-d52691b4dbfc