Get the GC to work again and change the allocator

Allocator subsystem works with a single contiguous chunk of memory.
Small object allocator uses fixed-size bins and never attempts to merge chunks,
and the large object allocator is a slightly-modified version of the SQLite
mem3.c allocator.
The GC uses the boundaries of this chunk of memory, plus a table of
flags, to determine if a Value refers to a heap allocation or not (we no longer have type information per-Value). The
current implementation requires storing the size of each heap object in
the GC header, but it should be possible to elide this requirement using flags (using 2 bits for each flag instead of 1, see golang GC implementation).
Should support expanding the heap via. sbrk or similar (will require
changing paw_Alloc to expand/contract the dynamic memory area, rather
than implement a realloc-like interface).

src/alloc.c

@@ -424,7 +424,7 @@ int pawZ_init(paw_Env *P, size_t heap_size)
     void *heap = OS_MALLOC(P, heap_size);
     if (heap == NULL) goto no_memory;
     H->heap = heap;
-printf("heap: %p-%p\n", heap,BUMP(heap,H->heap_size));
+
 #define SKIP_CHUNK(z) (heap = BUMP(heap, aligned(z)), \
                        heap_size -= aligned(z))
     H->a_block = heap;

src/alloc.h

@@ -23,7 +23,7 @@ struct GcFlag {
     uint8_t value;
 };
 
-#define FAST_BIN_COUNT 1024
+#define FAST_BIN_COUNT 64
 
 struct FastBins {
     struct BinInfo *info[FAST_BIN_COUNT];

test/test_alloc.c

@@ -25,7 +25,7 @@ static void alloc_and_free(paw_Env *P, size_t size)
     pawZ_alloc(P, ptr, size, 0);
 }
 
-#define MAX_DEFER 16384
+#define MAX_DEFER 32768
 static struct DeferredAlloc {
     void *ptr;
     size_t size;
@@ -105,14 +105,17 @@ static void test_lots_of_allocations(paw_Env *P)
         alloc_pattern(P, CAST_SIZE(rand() % 100 + 1));
     }
     for (size_t i = 0; i < 100; ++i) {
+        if(i==18){
+
+        }
         alloc_pattern(P, CAST_SIZE(rand() % 10000 + 1));
     }
     free_deferred_ptrs(P);
 }
 
 int main(void)
 {
-    driver(open_and_close);
-    driver(test_small_allocations);
+//    driver(open_and_close);
+//    driver(test_small_allocations);
     driver(test_lots_of_allocations);
 }