statistic: fix error when fast analyze on only indexes (#15889)#15967

Merged

sre-bot merged 3 commits intopingcap:release-3.0from sre-bot:release-3.0-5d846cfe7dfe

Apr 2, 2020

+24-3

Commits on Apr 1, 2020

cherry pick pingcap#15889 to release-3.0

lzmhhh123
authored and
sre-bot
committed
fix conflicts
lzmhhh123
committed

Commits on Apr 2, 2020

Merge branch 'release-3.0' into release-3.0-5d846cfe7dfe
sre-bot
authored