Summary: The type-erasing executor wrappers and the generic executor wrappers accept extra parameters to their `schedule` member functions, but nowhere is that functionality used, and such executor types would fail to satisfy the Executor concepts anyway. Remove that functionality.

Reviewed By: kirkshoop

Differential Revision: D14541290

fbshipit-source-id: 8cf0fd7bdc6dea72e43d5decc9e70ba843ab2db8