Substrate: build-only-wasm.sh appears outdated

[JoshOrndorff]

The script at .maintain/build-only-wasm.sh contains this logic:

https://github.com/paritytech/substrate/blob/7b002350a26b5013979b5b963ecea7626f860645/.maintain/build-only-wasm.sh#L22-L29

The directory it is testing for is of the form a/target/release/wbuild-runner/node-template-runtime. But in recent Substrate builds, that directory never exists. A set of similar directories with large numbers appended to the end exist. This makes the script always fall back to the else branch and just run cargo build --release -p node-template-runtime.

And thinking about it now, what was the other branch even supposed to do differently than that cargo command?

[kianenigma]

cc @bkchr

[bkchr]

cc @bkchr

Ty for pinging, but I already had seen the issue 😅😂