GC implementation for testing purposes
* Only works for a single mutator
* Runs on the same thread as the mutator
* Runs every nth checkpoint and after every m bytes are allocated
* Runs finalizers after sweeping on the mutator thread.
Integrating the stdlib with the thread states machinery requires
accessing to some parts of the new MM. This patch provides this
access by moving these parts to the main Memory.h header.
Some of unit-tests for the C++ part of the stdlib will require
thread state switching. In the new MM, we already have a helper
function that allows us to scopely initialize the memory subsystem
for a separate thread. This patch makes this helper available
for tests in the main runtime module by moving it to the main
ThreadSupport.hpp.
* test_support::TypeInfoHolder to create TypeInfo given payload description
* test_support::Object<Payload> to create objects with Payload and to get them from ObjHeader* after checking that their type_info are layout compatible.
* test_support::*Array<Count> to create various arrays with given length and similarly get them from ArrayHeader*.
Ilya Matveev