[ci] Include a log download link when test report is truncated (#117985)
Now "Download" will be a link to the file so people don't have to know
to open the build tab and find the download button.
This is a URL from a real build:
https://buildkite.com/organizations/llvm-project/pipelines/github-pull-requests/builds/123979/jobs/01937132-0fc3-4c95-a884-2fc0048cb9a7/download.txt
And this is how we can build it:
https://buildkite.com/organizations/{BUILDKITE_ORGANIZATION_SLUG}/pipelines/{BUILDKITE_PIPELINE_SLUG}/builds/{BUILDKITE_BUILD_NUMBER}/jobs/{BUILDKITE_JOB_ID}/download.txt
Given these env vars that were set in that job:
BUILDKITE_ORGANIZATION_SLUG="llvm-project"
BUILDKITE_PIPELINE_SLUG="github-pull-requests"
BUILDKITE_BUILD_NUMBER="123979"
BUILDKITE_JOB_ID="01937132-0fc3-4c95-a884-2fc0048cb9a7"
In theory these will always be available but:
1. Rather safe than sorry with this script, I don't want to make a
passing
build a failure because this script failed.
2. It would get very annoying if you had to set all these to test
the script locally.
llvm-project
71fd5288 - [ci] Include a log download link when test report is truncated (#117985)
