Roboto appears to be licensed under Apache 2.0. Noto under SIL Open Font license.

As these fonts are purportedly intended for testing purposes, presumably they will be included in the package. Adding additional licenses to the codebase complicates the usage. You might agree to the terms of the Go license, but not the Apache license, for instance.

Since this new font is licensed under the Go license, there is only one set of terms you need to agree to. This is a much better situation for many reasons.