Fix run_quantize_ceil().

In practice this bug had limited impact (and then only by increasing
chunk fragmentation) because run_quantize_ceil() returned correct
results except for inputs that could only arise from aligned allocation
requests that required more than page alignment.

This bug existed in the original run quantization implementation, which
was introduced by 8a03cf039cd06f9fa6972711195055d865673966 (Implement
cache index randomization for large allocations.).

src/arena.c

@@ -185,7 +185,7 @@ run_quantize_ceil(size_t size)
 		 * search would potentially find sufficiently aligned available
 		 * memory somewhere lower.
 		 */
-		qsize = run_quantize_ceil_hard(size);
+		qsize = run_quantize_ceil_hard(qsize);
 	}
 	return (qsize);
 }