try to pass vm around instead of (heap, interns)

[davidhewitt]

This WIP attempts to pass vm around more places instead of heap, interns as separate pieces borrowed out of VM. This might help me with problems I'm facing in #207, but it's possible there are other ways to solve it.

I think this refactoring would be necessary if monty ever supports the class statement, as the vm would be needed to run all the user code for magic methods such as __len__ etc.

I think it might also be completely reasonably to not do this and commit to not supporting user-defined classes. I can imagine that user-defined classes are extremely hard to support in the face of suspendable execution, as basically the entire interpreter could suspend at any point, so I think a lot of the code which is currently implemented as Rust would instead have to be rewritten as micro-ops which could be individually suspended. (That might ultimately pay out, but it seems risky / hard / potentially impossible for all code paths, such as when finding hash entry inside a dictionary.)

[codspeed-hq]

Merging this PR will degrade performance by 13.15%

❌ 1 regressed benchmark
✅ 12 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
❌	fib__monty	157.9 ms	181.8 ms	-13.15%

---

_{Comparing dh/pass-vm (cfabaa8) with main (353f982)}

[codecov]

Codecov Report

❌ Patch coverage is 63.31310% with 423 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
crates/monty/src/heap_data.rs	27.50%	87 Missing ⚠️
crates/monty/src/heap.rs	55.11%	52 Missing and 5 partials ⚠️
crates/monty/src/object.rs	45.00%	20 Missing and 13 partials ⚠️
crates/monty/src/types/dict.rs	69.72%	8 Missing and 25 partials ⚠️
crates/monty/src/types/set.rs	60.29%	14 Missing and 13 partials ⚠️
crates/monty/src/value.rs	77.55%	16 Missing and 6 partials ⚠️
crates/monty/src/repl.rs	58.00%	20 Missing and 1 partial ⚠️
crates/monty/src/types/list.rs	73.41%	3 Missing and 18 partials ⚠️
crates/monty/src/types/py_trait.rs	9.52%	19 Missing ⚠️
crates/monty/src/types/tuple.rs	51.51%	2 Missing and 14 partials ⚠️
... and 26 more

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