objgenerator: Store proper code_info pointer.
objgenerator.throw(): Throwing GeneratorExit is equivalent to .close().

According to PEP380 and caught by CPython test_pep380.py .
objgenerator.throw: Instantiate if exception type passed, just as "raise".

Caught by CPython test_pep380.py.
objexcept: Fix another place missing proper args tuple initialization.