Add a workaround for people that use *args instead of listing (#166883)

parameters when defining the scripting interfaces.

We try to count the parameters to make sure the user has defined them
correctly, but this throws the counting off.

I'm not adding a test for this because then it would seem like we
thought this was a good idea. I'd actually rather not support it
altogether, but we added the parameter checking pretty recently so there
are extant implementations that we broke. I only want to support them,
not suggest anyone else do this going forward.

Author: jimingham

lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedPythonInterface.h

@@ -188,8 +188,13 @@ class ScriptedPythonInterface : virtual public ScriptedInterface {
       // This addresses the cases where the embedded interpreter session
       // dictionary is passed to the extension initializer which is not used
       // most of the time.
+      // Note, though none of our API's suggest defining the interfaces with
+      // varargs, we have some extant clients that were doing that.  To keep
+      // from breaking them, we just say putting a varargs in these signatures
+      // turns off argument checking.
       size_t num_args = sizeof...(Args);
-      if (num_args != arg_info->max_positional_args) {
+      if (arg_info->max_positional_args != PythonCallable::ArgInfo::UNBOUNDED &&
+          num_args != arg_info->max_positional_args) {
         if (num_args != arg_info->max_positional_args - 1)
           return create_error("Passed arguments ({0}) doesn't match the number "
                               "of expected arguments ({1}).",