Revert "[hack] Fix type error in framework perf script"

Summary: This reverts commit e9fed0cb2ffdf0225d4cc90f16b09f035495124d.

9f7ffd38dac09d9e73c4a5a02d99699546ed41e5 has fixed the typechecker to handle
exit() properly.

Reviewed By: @ptarjan

Differential Revision: D1590510