Enables finding out anywhere whether the thread is processing a call
from an Automation client. Not sure how I have managed without this
until now.

Presumably the Invocation_Impl::mbFromOLE variable in stoc can be
replaced by a call of comphelper::Automation::AutomationInvokedZone::
isActive().

Change-Id: Ib79ec5f6dff17af25c8539d2907c7cd5d7b9a62c