[andreas-karlsson]

Fixes #249. An alternative to #251.

Adds MachineFactoryCompiler.Builder.compileModule(), which returns a CompiledModule: the machine factory plus a copy of the module without the parsed bodies of compiled functions. It keeps only the bodies the interpreter may still run: the interpreted functions, plus any function they reach through tail calls. A new Instance.builder(CompiledModule) creates instances from it.

var compiled = MachineFactoryCompiler.builder(module).compileModule();
var instance = Instance.builder(compiled).build();

The module passed in is left unchanged, and compile() works as before. Nothing is dropped if an indirect tail call makes the reachable functions unknown, or when the compilation is loaded from the cache. Accessing a dropped body throws an IllegalStateException.

Heap after compile, keeping only the CompiledModule:

	Data section	main	This PR
3.5 MB module	3.2 MB	15 MB	5 MB
14 MB module, 5k functions	12.4 MB	72 MB	18 MB

Parse and compile times are unchanged.

Compared with #251, this keeps WasmModule immutable, at the cost of a new compile method and an Instance.builder overload. Both are additive, so binary compatibility is kept.

A possible follow-up: most of the remaining heap is data segments. If the compiled module kept the segments next to the module copy instead of inside it, instances wouldn't pin them through their module, and they could be freed once nothing needs them.