Wrong binaryen release downloaded for linux aarch64

[JakeOShannessy]

In the function binaryenUrl converts aarch64 to arm64 to produce the URL to download binaryen. This is the correct behviour for mac, but on linux the correct architecture label for aarch64 releases is just aarch64.

wasmbuild/lib/wasmopt.ts

Line 124 in 816dc32

"aarch64": "arm64",

The correct URL for linux aarch64 should be (assuming binaryen version_130):

https://github.com/WebAssembly/binaryen/releases/download/version_130/binaryen-version_130-aarch64-linux.tar.gz

not

https://github.com/WebAssembly/binaryen/releases/download/version_130/binaryen-version_130-arm64-linux.tar.gz

which is what is produced currently.