Reduce maximum tested alignment.

Reduce maximum tested alignment from 2^29 to 2^25.  Some systems may not
have enough contiguous virtual memory to satisfy the larger alignment,
but the smaller alignment is still adequate to test multi-chunk
alignment.

test/integration/mallocx.c

@@ -1,8 +1,7 @@
 #include "test/jemalloc_test.h"
 
 #define	CHUNK 0x400000
-/* #define MAXALIGN ((size_t)UINT64_C(0x80000000000)) */
-#define	MAXALIGN ((size_t)0x2000000LU)
+#define	MAXALIGN (((size_t)1) << 25)
 #define	NITER 4
 
 TEST_BEGIN(test_basic)