C#: Add test for the new lock type.

Author: michaelnebel

csharp/ql/test/library-tests/statements/Lock3.expected

@@ -0,0 +1 @@
+| statements.cs:285:13:288:13 | lock (...) {...} | statements.cs:285:19:285:28 | access to field lockObject | Lock | statements.cs:286:13:288:13 | {...} |

csharp/ql/test/library-tests/statements/Lock3.ql

@@ -0,0 +1,8 @@
+import csharp
+
+from Method m, LockStmt ls, Expr lockExpr
+where
+  ls.getEnclosingCallable() = m and
+  m.getName() = "LockMethod" and
+  lockExpr = ls.getExpr()
+select ls, lockExpr, lockExpr.getType().toString(), ls.getBlock()