C#: Add test

Author: calumgrant

csharp/ql/test/query-tests/Dead Code/DeadStoreOfLocal/DeadStoreOfLocal.cs

@@ -259,7 +259,7 @@ void M7()
         fn(() =>
         {
             var x = y;  // BAD: Dead store in lambda
-        return 0;
+            return 0;
         });
     }
 
@@ -425,3 +425,14 @@ int M(bool b)
         return i;
     }
 }
+
+public static class AnonymousVariable
+{
+    public static int Count<T>(this IEnumerable<T> items)
+    {
+        int count = 0;
+        foreach (var _ in items)
+            count++;
+        return count;
+    }
+}

csharp/ql/test/query-tests/Dead Code/DeadStoreOfLocal/DeadStoreOfLocal.expected

@@ -16,6 +16,7 @@
 | DeadStoreOfLocal.cs:320:9:320:32 | ... = ... | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocal.cs:316:23:316:23 | b | b |
 | DeadStoreOfLocal.cs:361:13:361:20 | String s = ... | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocal.cs:361:13:361:13 | s | s |
 | DeadStoreOfLocal.cs:387:13:387:21 | ... = ... | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocal.cs:385:13:385:13 | s | s |
+| DeadStoreOfLocal.cs:434:22:434:22 | T _ | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocal.cs:434:22:434:22 | _ | _ |
 | DeadStoreOfLocalBad.cs:7:13:7:48 | Boolean success = ... | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocalBad.cs:7:13:7:19 | success | success |
 | DeadStoreOfLocalBad.cs:23:32:23:32 | FormatException e | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocalBad.cs:23:32:23:32 | e | e |
 | DeadStoreOfLocalBad.cs:32:22:32:22 | String s | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocalBad.cs:32:22:32:22 | s | s |