Added dead stores test case.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@53966 91177308-0d34-0410-b5e6-96231b3b80d8

test/Analysis/dead-stores.c

@@ -72,4 +72,10 @@ int f10() {
   return 1;
 }
 
+int f11() {
+  int x = 4;
+  return ++x; // no-warning
+}
+
+