Compiling a string annotation containing a lambda with keyword-only argument without default value causes a crash.

from __future__ import annotations
def f() -> (lambda *, x: x): pass

The following PR fixes this crash. It also fixes other errors:

* Removes a space between "lambda" and ":" in the representation of lambda without argument.

* Removes the final "*" (it is incorrect syntax) in the representation of lambda without *args and keyword-only arguments when compile from AST.