Add an option to build executables (including test suites/benchmarks) using bytecode #12515

Cabal already supports either dynamically or statically linking executables.
I suggest we should also allow building bytecode executables, which would include test suites and benchmarks.

Motivation

The main motivation for this is to benefit from the speed of a workflow that makes use of bytecode, eg, when using cabal repl, but with the ease of use of your standard CLI flags. So, cabal build all and cabal test all would do what you would expect normally but producing executables that just load generated bytecode.

This would likely require support for GHC's new .gbc files.

cc @fendor