The original attempt at handling the returns from loadModuleFn wasn't ideal. 889cae5ff1
Instead of making the host go via the VM allocation and need to understand it semantically, we can instead solve the problem of the unfreed return result directly.
This also opens up the option of providing a length parameter or other information needed later (length is optional, and not used as of right now, but exists to show intent).
This prevents a memleak, noticeable when running `wren_test` under
`valgrind`. For example, the following command would leak
`./bin/wren_test_d any_example.wren`
