https://build.golang.org/log/bcb53a27f560f5363c22056d02f2a968ca351370 is marked as a failure in the build dashboard:

However, the log doesn't indicate what failed: the log does not include the word FAIL or any output that includes a goroutine dump, timeout indication, or signal. (It looks like it might have either hung or crashed during the API check, but without a goroutine or process dump there is no clear way to diagnose the problem further.)