Instead of being boxed for each node, the `Instruction` type contains a boxed variable-size elements. Thus `Instruction` is quite lean, and the allocator deals with variable-sized elements.
Total number of allocations is more or less same, but less space is wasted for unused memory: previously the Instruction's size was 112 bytes in WASM, now it is 16.
It reduces memory consumption on large AIR scripts (heap size decreased from 7.7MiB to 4.625MiB in parser-10000-100, and for the new parser-calls-10000-100 benchmark, it decreased from 5.115MiB to 4.375MiB).
This is a breaking change as the API changes (though the code that navigates the parsed tree generally should work as is).
* chore(benchmark): clear stale benchmark data
Originally, benchmark util merge benchmark data, i.e. only inserted new
data in the benchmark store. However, sometimes benches disappear, and
incorrect information is stored for them (i.e. AquaVM version which is
per-machine).
However, sometimes this functionality is useful, when you want to add a
new benchmark without running all the others. For such case,
`aquavm_performance_metergin run --unsafe-merge-results` option is
added.
* Restore the `null` benchmark
* Do text report generation exactly one time
It was regenerated from 0 to N times before, and it is wrong.
