v357

• Migrated Node.js version-resolution build errors (unresolvable version, invalid semver requirement) onto the call-site failure-classification framework. The error messages are unchanged. (#1687)
• Migrated Node.js download and checksum-validation build errors onto the failure-classification framework, and removed the obsolete AWS proxy (NO_PROXY=amazonaws.com) build warning, which dated to when Node.js binaries were served from an S3 mirror. (#1688)