build: canonicalize to EC2 machine architecture

[jahkeup]

Issue number:

n/a

Description of changes:

There are places in which architectures may/must be provided vary in which identifier should be provided, like aarch64 and arm64. The amiize.sh script would get very far before an error is raised about an incorrect choice on the part of the caller. Instead of waiting until the aws ec2 register-image call, the script will now bail on invalid architectures and also will canonicalize the given value from a supported set (eg: aarch64 -> arm64).

This handles callers providing a mix of identifiers and maps to the
correct EC2 identifier.

Signed-off-by: Jacob Vallejo <jakeev@amazon.com>

Testing done:

I ran ./amiize.sh with --arch aarch64 and had a successful image on the other side.

Terms of contribution:

By submitting this pull request, I agree that this contribution is dual-licensed under the terms of both the Apache License, version 2.0, and the MIT license.