report: report fuzzer fatal errors

[avagin]

Right now, all fuzzer fatal errors are hidden in "lost connection to test machine" or "no output from test machine" reports.

[codecov]

Codecov Report

Merging #3101 (2f3839d) into master (2738b39) will decrease coverage by 0.0%.
The diff coverage is 0.0%.

Impacted Files	Coverage Δ
pkg/log/log.go	62.8% <0.0%> (ø)
pkg/report/report.go	83.7% <ø> (ø)
syz-fuzzer/proc.go	0.0% <0.0%> (ø)
pkg/vcs/git.go	58.4% <0.0%> (-1.1%)	⬇️

[dvyukov]

I afraid we can get 30 new bugs for each of 15 kernels over the next month. I would be more conservative and put them all into a single bucket for now. If there is a spike, it's possible to assess which ones are firing manually.

It's also possible to use the "AltTitle" thing to merge them all together.
If we do Title=full-message and AltTitle=SYZFATAL, then they will be merged into a single bug (grouped by AltTitle), but the full-message will be visible for each crash in the "Title" column on the dashboard.
The only downside is that the name of the bug will be a random full message of one of the crashes (the first one that will create the bug).

[avagin]

@dvyukov I have added the alt title.