[mypyc] Remove unreachable code

See #19050 for context.

Author: JukkaL

mypyc/test/test_cheader.py

@@ -32,8 +32,6 @@ def check_name(name: str) -> None:
             registry.function_ops.values(),
         ]:
             for ops in values:
-                if isinstance(ops, PrimitiveDescription):
-                    ops = [ops]
                 for op in ops:
                     if op.c_function_name is not None:
                         check_name(op.c_function_name)