Support: Databricks and generic: fix for values as table name

[jmhain]

In the previous release, we added support for VALUES tables in a FROM clause without a containing subquery, as supported by Snowflake and Databricks. However, this caused a regression in DataFusion which considers values a valid table name. I did some testing and Databricks permits this as well (Snowflake does not).

[coveralls]

Pull Request Test Coverage Report for Build 9149778305

Details

• 38 of 43 (88.37%) changed or added relevant lines in 3 files are covered.
• 10 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.03%) to 89.462%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/ast/query.rs	3	4	75.0%
tests/sqlparser_databricks.rs	32	36	88.89%

Files with Coverage Reduction	New Missed Lines	%
tests/sqlparser_databricks.rs	10	85.84%

Totals
Change from base Build 9117210757:	-0.03%
Covered Lines:	24926
Relevant Lines:	27862

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💛 - Coveralls

[alamb]

Thank you @jmhain