During creation of an `InstanceHandle` if a link error occurred (such as an element segment doesn't fit) then the instance itself would be leaked by accident. This commit fixes the issue by ensuring that an `InstanceHandle` is created very quickly so if any initialization later fails it will be cleaned up through normal destructors.
This is the wasmtime-runtime crate, which contains wasm runtime library
support, supporting the wasm ABI used by wasmtime-environ,
wasmtime-jit, and wasmtime-obj.
This crate does not make a host vs. target distinction; it is meant to be compiled for the target.