this PR improves 3-6% for `prepare` benchmark without slowing down
others. After this PR we don't have to store `InsnFunction` in
`Program` and `ProgramBuilder` anymore, because `to_function` will
return result without matching.
Reviewed-by: Preston Thorpe <preston@turso.tech>
Closes#3098
To be used in DBSP-based projections. This will compile an expression
to VDBE bytecode and execute it.
To do that we need to add a new type of Expression, which we call a
Register.
This is a way for us to pass parameters to a DBSP program which will be
not columns or literals, but inputs from the DBSP deltas.
