WASM modules with `_` (underscore) in the filename causes Spin to panic

[mikkelhegn]

It seems that the SDK is having trouble with wasm modules using _ (underscore) in the file name.

Creating a project using the http-csharp template and calling it from_branch resulted in the following error when curl'ing the endpoint (build and up works)

2022-09-02T08:48:56.664013Z ERROR spin_http_engine: Error processing request: wasm trap: out of bounds memory access
wasm backtrace:
    0: 0x40e312 - <unknown>!dlfree
note: using the `WASMTIME_BACKTRACE_DETAILS=1` environment variable to may show more debugging information

Creating a project with no _ in the name does not have this error and works.

I tried the Rust SDK and http-rust template, and it does not have this issue.