Avoid a too-large pointer literal in StlVectorTest

Summary: [Folly] Avoid a too-large pointer literal in StlVectorTest, keeping the literal value divisible by 8 to avoid ubsan violations.

Reviewed By: igorsugak

Differential Revision: D19170467

fbshipit-source-id: 2c93d2b3d9f7515761668d3364c4b8b5093a6145

folly/test/stl_tests/StlVectorTest.cpp

@@ -541,7 +541,7 @@ struct DataTracker : Tracker {
     }
     print("~Data()");
     uid = 0xdeadbeef;
-    self = (DataTracker*)0xfeebdaed0;
+    self = (DataTracker*)0xdead1010;
   }
 
   DataTracker& operator=(const DataTracker& o) noexcept {