Fix issues where reported LSL compiler error line numbers do not match the script.

This is probably due to changes in the layout of the generated script preamble (using statements etc, ) in c8afc852 (Jan 17 2013).
Re-enabled existing regression test that exercises at least one case of this.

OpenSim/Region/ScriptEngine/Shared/CodeTools/CSCodeGenerator.cs

@@ -162,7 +162,7 @@ namespace OpenSim.Region.ScriptEngine.Shared.CodeTools
             m_braceCount++;
 
             // line number
-            m_CSharpLine += 3;
+            m_CSharpLine += 9;
 
             // here's the payload
             retstr += GenerateLine();