Fix bug with empty Wasm file when using system binaryen for optimization (#179)

* Revert me: Hotfix for funty issue

* Assert that size of resulting wasm is > 0

* Ensure optimized file is not overwritten with empty file on `not(feature = binaryen-as-dependency)`

* Fix `warning: panic message is not a string literal`

* Do not record debug info

* Update comments