fix mr pool options test

Author: davebayer

thrust/testing/mr_pool_options.cu

@@ -11,6 +11,7 @@ void TestPoolOptionsBasicValidity()
   options.max_bytes_per_chunk  = 1024 * 1024;
   options.smallest_block_size  = 8;
   options.largest_block_size   = 1024;
+  options.alignment            = 4;
   ASSERT_EQUAL(options.validate(), true);
 
   // the minimum number of blocks per chunk is bigger than the max
@@ -42,6 +43,7 @@ void TestPoolOptionsComplexValidity()
   options.max_bytes_per_chunk  = 1024 * 1024;
   options.smallest_block_size  = 8;
   options.largest_block_size   = 1024;
+  options.alignment            = 4;
   ASSERT_EQUAL(options.validate(), true);
 
   options.min_bytes_per_chunk = 2 * 1024;