module: validate that strip-types does not insert any code

We can do this while the mode is strip-types only

The wasm binary is not expected to insert any other changes in the sourcecode except for the allowed symbols / patterns We can use this to increase trust in the code that wasm binary outputs

It is still possible to do unexpected things under this limitation, but it makes anything funny much harder for a supply chain attack

Now does this if internal swc lib is e.g. switched to a codegen mode unexpectedly:

Existing tests should pass, this is just a safeguard Should also add some multi-byte stripping tests