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### _Why are the changes needed?_
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`subdomain` is a widely used term in computer science
### _How was this patch tested?_
- [x] Add some test cases that check the changes thoroughly including negative and positive cases if possible
- [ ] Add screenshots for manual tests if appropriate
- [x] [Run test](https://kyuubi.readthedocs.io/en/latest/develop_tools/testing.html#running-tests) locally before make a pull request
Closes#1010 from yaooqinn/subdomain.
Closes#1010
72ed19a3 [Kent Yao] address comments
4dcae414 [Kent Yao] fix test
c3bb788d [Kent Yao] Rename engine.share.level.sub.domain to engine.share.level.subdomain
b7762357 [Kent Yao] Rename engine.share.level.sub.domain to engine.share.level.subdomain
Authored-by: Kent Yao <yao@apache.org>
Signed-off-by: Kent Yao <yao@apache.org>
d375eb0cfc