[jnc_ct] critical bugfix: don't fallback to llvm cast post-compile
[jnc_ct] critical bugfix: don't fallback to llvm cast post-compile

const casts can happen at runtime (for instance, for variant casts), but failing const cast at runtime should not result in retry using full llvm cast.

vovkos/jancy,vovkos/jancy,vovkos/jancy,vovkos/jancy,vovkos/jancy