Give an error when StepUsingScriptedThreadPlan is passed a bad classname.

Differential Revision: https://reviews.llvm.org/D68173

llvm-svn: 373135

lldb/unittests/ScriptInterpreter/Python/PythonTestSuite.cpp

@@ -95,6 +95,7 @@ LLDBSwigPythonCreateCommandObject(const char *python_class_name,
 
 extern "C" void *LLDBSwigPythonCreateScriptedThreadPlan(
     const char *python_class_name, const char *session_dictionary_name,
+    std::string &error_string,
     const lldb::ThreadPlanSP &thread_plan_sp) {
   return nullptr;
 }