Substitute pow2bin allocator with a dlmalloc based allocator (#71)

* Add dlmalloc_strat allocator strategy
 - Use mspace variant to ease encapsulation
 - Make pow2bins and dlmalloc cmake selectable
* Add unit tester for dlmalloc, rework single_heap, pow2bins unit testers
accordingly
 - add dlmalloc get_used/get_avail, and have all strats allocators also have a get_used
 - Rework memallocator unit tests: bin size is per strat, alignment is verified in singleheap
* bugfix: dlmalloc exposed that the pingpong test would write past end of
allocation with -w 32
* iostream leakage/mixed usage of cerr and fprintf(stderr

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Signed-off-by: Aurelien Bouteiller <aurelien.bouteiller@amd.com>

src/memory/single_heap.cpp

@@ -61,7 +61,7 @@ char* SingleHeap::get_base_ptr() { return heap_mem_.get_ptr(); }
 
 size_t SingleHeap::get_size() { return heap_mem_.get_size(); }
 
-size_t SingleHeap::get_used() { return strat_.amount_proffered(); }
+size_t SingleHeap::get_used() { return strat_.get_used(); }
 
 size_t SingleHeap::get_avail() { return get_size() - get_used(); }