fix: Avoid using online normalization for MetaData.create_all.

[DanCardin]

The assumption is generally that with MetaData.create_all, it's being used to create objects from an empty database, and thus, there's less/little point in doing live/connection based normalization; since there wont be an existing view to compare against.

In particular, this change fixes the case where a view (A) dependent on another view (B) are both being created in the same comparison pass (i.e. during MetaData.create_all), and the comparison for view A tries to create itself in order to get a normalized view, only to realize that view B doesn't exist.

[coveralls]

Pull Request Test Coverage Report for Build 4493585357

• 6 of 6 (100.0%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 96.783%

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Totals
Change from base Build 4365875483:	0.0%
Covered Lines:	1677
Relevant Lines:	1731

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💛 - Coveralls