roachtest: election-after-restart failed

[cockroach-teamcity]

SHA: https://github.com/cockroachdb/cockroach/commits/0dba537ae88e495ddf29b4c347b4c30ee99bd046

Parameters:

To repro, try:

# Don't forget to check out a clean suitable branch and experiment with the
# stress invocation until the desired results present themselves. For example,
# using stress instead of stressrace and passing the '-p' stressflag which
# controls concurrency.
./scripts/gceworker.sh start && ./scripts/gceworker.sh mosh
cd ~/go/src/github.com/cockroachdb/cockroach && \
make stressrace TESTS=election-after-restart PKG=roachtest TESTTIMEOUT=5m STRESSFLAGS='-maxtime 20m -timeout 10m' 2>&1 | tee /tmp/stress.log

Failed test: https://teamcity.cockroachdb.com/viewLog.html?buildId=983962&tab=buildLog

The test failed on release-2.1:
	asm_amd64.s:574,panic.go:502,panic.go:63,signal_unix.go:388,log.go:172,log.go:216,cluster.go:221,cluster.go:695: runtime error: invalid memory address or nil pointer dereference

[andreimatei]

Logging crash. Fixing in #31822.