While most applications will just create ALL_ACCESS handles which
support the additional operations FEX needs over the regular windows syscall
(usually just QUERY_INFORMATION to lookup the thread object), it is
valid for them to pass in the minimal set required for each operation
and windows/wine will reject any other operations (e.g. querying the TEB
base on a handle with only the SUSPEND right). Windows permits
duplicating handles to extend their permissions given the process itself
has such permissions, so do that as necessary for the operations FEX
needs.
In the terminate case, if we don't return early then we will delete the
FEX thread object but the actual terminate call that follows will
fail, leaving the thread in a bad state.