[GTK] JSCore.gir.in has a few problems

[GTK] JSCore.gir.in has a few problems
https://bugs.webkit.org/show_bug.cgi?id=114710

Reviewed by Philippe Normand.

.:

* GNUmakefile.am: Move common GIR initialization here from WebKit1.
* configure.ac: Updated to reflect new JSC gir file location.

Source/JavaScriptCore:

* GNUmakefile.am: Add the gobject introspection steps for JavaScriptCore here,
because they are shared between WebKit1 and WebKit2.
* JavaScriptCore.gir.in: Added. Moved from the WebKit1 directory. Now written
as foreign interfaces and referencing the javascriptcoregtk library.

Source/WebKit/gtk:

* GNUmakefile.am: Updated to reflect new name and location of JavaScriptCore-x.0.gir.
* JSCore.gir.in: Removed.

Source/WebKit2:

* GNUmakefile.am: Updated to reflect new location of JavaScriptCore gir file. Share the
same autotools data task as the WebKit1 and JavaScriptCore gir installations.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@148755 268f45cc-cd09-0410-ab3c-d52691b4dbfc