Correct an issue when winning "arc anoid" with certain terminal dimensions

Summary: See PHI2085. Python 3 is stricter about integers and floats than Python 2 was, and we can end up passing a float where an integer was expected if the player wins "arc anoid" using a terminal with certain (most?) character dimensions.

Test Plan:

• Modified "arcanoid.py" to win instantly.
• Adjusted terminal window to 80x24, ran "arc anoid", reproduced crash.
• Ran "python2 arcanoid.py" and observed old victory animation behavior.
• Applied patch.
• Ran "arc anoid" and observed identical victory animation behavior.

Differential Revision: https://secure.phabricator.com/D21667