Use new _implicitNameOp() to generate name op code for list comprehensions.

Always emit a SET_LINENO 0 at the beginning of the module.  The
builtin compiler does this, and it's much easier to compare bytecode
generated by the two compilers if they both do.

Move the SET_LINENO inside the FOR_LOOP block for list
comprehensions.  Also for compat. with builtin compiler.
2 files changed