Edited Issue: UpForGrabs: Use non-obsolete Monitor.Enter methods [424]

LockedAssemblyCache currently has this code:

internal LockedAssemblyCache(object lockObject, Dictionary<Assembly, ImmutableAssemblyCacheEntry> globalAssemblyCache)
{
_lockObject = lockObject;
_globalAssemblyCache = globalAssemblyCache;
#pragma warning disable 0618
//@TODO: This overload of Monitor.Enter is obsolete. Please change this to use Monitor.Enter(ref bool), and remove the pragmas -- ericeil
Monitor.Enter(_lockObject);
#pragma warning restore 0618
}