x/build: test whether Go core changes break external tools and debuggers #18144
Description
Changes to the Go core (compiler output, libraries, x/tools) can break tools and debuggers that build on them, such as gocode (@nsf), Delve (@derekparker), and Backtrace's ptrace (@abelmathew). While those tool authors can test for breakages against tip, it might be useful for us to know when CLs submitted to the Go core break tools that are important to the Go community. We should work with the authors to ensure the tools are fixed for each new Go release.
@bradfitz suggested we may be able to extend the builders to help with this testing.