修复Oracle 19c备份时报错不支持CONTINOUS_MINE

[ZhuhongLee]

解决Oracle 19c 非CDB容器部署，生成回滚语句报不支持CONTINOUS_MINE的问题，若是CDB容器部署，暂不支持备份

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 13 lines in your changes are missing coverage. Please review.

Project coverage is 76.77%. Comparing base (5f556a5) to head (5e3b021).

Files	Patch %	Lines
sql/engines/oracle.py	0.00%	13 Missing :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2553      +/-   ##
==========================================
- Coverage   76.82%   76.77%   -0.05%     
==========================================
  Files         117      117              
  Lines       16073    16083      +10     
==========================================
  Hits        12348    12348              
- Misses       3725     3735      +10     

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[LeoQuote]

lint 必须要过，自己用black再整理一下，覆盖率尽量达标

[LeoQuote]

https://github.com/hhyo/Archery/blob/5f556a522faa0b680ef09ffc23dd42d9f1dfc8dd/sql/engines/tests.py#L1447-L1459 你照着试试写一下测试