Bug 7772 – Remove volatile statements from core.thread

This is problematic for build tools that manually compile druntime/phobos. Without -d core.thread won't compile. I don't know why it's ok to ship code with DMD that requires deprecated features: D:\DMD\dmd2\src\druntime\src\core\thread.d(888): volatile statements deprecated; use synchronized statements instead D:\DMD\dmd2\src\druntime\src\core\thread.d(2953): volatile statements deprecated; use synchronized statements instead D:\DMD\dmd2\src\druntime\src\core\thread.d(3960): volatile statements deprecated; use synchronized statements instead D:\DMD\dmd2\src\druntime\src\core\thread.d(3968): volatile statements deprecated; use synchronized statements instead D:\DMD\dmd2\src\druntime\src\core\thread.d(3995): volatile statements deprecated; use synchronized statements instead D:\DMD\dmd2\src\druntime\src\core\thread.d(4004): volatile statements deprecated; use synchronized statements instead

This now done.

Thanks.