Implement use-after-free detection using junk and stash.

On deallocation, sampled pointers (specially aligned) get junked and stashed
into tcache (to prevent immediate reuse).  The expected behavior is to have
read-after-free corrupted and stopped by the junk-filling, while
write-after-free is checked when flushing the stashed pointers.

src/cache_bin.c

@@ -2,6 +2,8 @@
 #include "jemalloc/internal/jemalloc_internal_includes.h"
 
 #include "jemalloc/internal/bit_util.h"
+#include "jemalloc/internal/cache_bin.h"
+#include "jemalloc/internal/safety_check.h"
 
 void
 cache_bin_info_init(cache_bin_info_t *info,