Standardize platform naming

Existing platform names listed in https://github.com/adoptium/aqa-tests/blob/master/buildenv/jenkins/openjdk_tests are not unified. For example, some platform has -64 (e.g., x86-64_linux) but others has 64 (e.g., aarch64_linux). We would like use regex of platforms to specify test requirements, so it is needs to be standardized and intuitive to use.

Start by reading buildenv/jenkins/openjdk_tests and inventory the existing platform names, including x86-64_linux and aarch64_linux. Determine a consistent naming convention that remains intuitive for regex-based test requirements, then update the affected entries. Done means the platform names are standardized throughout the file and the resulting patterns are usable for specifying test requirements.

Written by the indexing model from the issue text.