This change makes it possible to exclude formats using compile time
options. BC7 is *never* exposed on the web and it has an absolutely huge
coding table which means we're just wasting space.
basis_transcoder.js 58707
basis_transcoder.wasm 224404
The impact on the file size is enormous, and it's used to output one
line into console which isn't exposed through the API anyhow.
basis_transcoder.js 58707
basis_transcoder.wasm 705079
