Remove non-x86_64 architectures build from our travis config (#2777)
Remove non-x86_64 architectures build from our travis config (#2777)

These have not been working since #1554, where we switch to using
an alpine docker image rather than the alpine sysroot install
script (that honors the ARCH environment variable).

So nobody has noticed in the last 2 years that we've been releasing
copies of x86_64 binaries.  e.g: this file actually contains x86_64
binaries:
 https://github.com/WebAssembly/binaryen/releases/download/version_91/binaryen-version_91-aarch64-linux.tar.gz

What is more its not really our job to release binaries for all these
different architectures.  We can let downstream distos do that.

Node itself doesn't ship 32bit x86 linux images.
WebAssembly/binaryen,WebAssembly/binaryen,WebAssembly/binaryen,WebAssembly/binaryen,WebAssembly/binaryen