Add regression test to check that specifying a non-existent event raise a syntax error

This was the case before any of the recent changes

OpenSim/Region/ScriptEngine/Shared/CodeTools/Tests/LSL_EventTests.cs

@@ -38,6 +38,15 @@ namespace OpenSim.Region.ScriptEngine.Shared.Tests
     {
         CSCodeGenerator m_cg = new CSCodeGenerator();
 
+        [Test]
+        public void TestBadEvent()
+        {
+            TestHelpers.InMethod();
+//            TestHelpers.EnableLogging();
+
+            TestCompile("default { bad() {} }", true);
+        }
+
         [Test]
         public void TestMovingEndEvent()
         {