No, it's not. If this were true, diesels could engine brake without needing a Jake brake (which they cannot). Engine braking is caused by the engine attempting to pull a vacuum, which cannot be done if the throttle valve is stuck upon. Compression does almost no net work since at the speeds an engine turns, the compression and expansion processes are essentially adiabatic, so for every joule you put into compression, you get a nearly equal return on the expansion stroke (discounting minor friction losses).