Fix size class overflow handling when profiling is enabled.

Fix size class overflow handling for malloc(), posix_memalign(),
memalign(), calloc(), and realloc() when profiling is enabled.

Remove an assertion that erroneously caused arena_sdalloc() to fail when
profiling was enabled.

This resolves #232.

test/include/test/jemalloc_test.h.in

@@ -1,3 +1,7 @@
+#include <limits.h>
+#ifndef SIZE_T_MAX
+#  define SIZE_T_MAX	SIZE_MAX
+#endif
 #include <stdlib.h>
 #include <stdarg.h>
 #include <stdbool.h>