Use the wasmtime-cranelift for winch component trampolines

[elliottt]

Instead of reimplementing the component trampolines directly in terms of Winch's MacroAssembler trait, reuse wasmtime-cranelift's Compiler implementation to do that heavy lifting.

I had to remove the type parameter from CompiledFunction and make it a boxed dyn Trait to make this work, due to the requirements of Compiler::append_code, and the visibility of ModuleTextBuilder in the crate hierarchy. I think that this refactoring could be pushed further to avoid the need to have the Compiler trait interface produce &dyn Any results for compiled functions, but haven't looked into making changes further than what was needed to get component trampolines working here.

We can push this work further to remove all trampoline generation from the wasmtime-winch crate, however I didn't want to bulk out the diff in this PR with that additional change, as it's not necessary for running components with winch.

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