Investigate -fprefer-byte-code with head.hackage

The goal of this ticket is to run head.hackage with -fwrite-if-simplified-core -fbyte-code-and-object-code -fprefer-byte-code, and investigate any failures (possibly opening new tickets). This requires GHC 9.6/master with fixes to known bugs: !9750 (closed) and !9863 (closed).

The rationale is that -fprefer-byte-code can run the interpreter on optimised code and this hasn't been tested thoroughly yet.

If it goes well, potentially we could support ghci -O.

Edited Jan 31, 2023 by Krzysztof Gogolewski

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