[Test-only](7.1.x) HHH-11910 SchemaUpdateTest fails on databases using case-insensitive identifiers

SchemaUpdateTest is explicitly skipped for SQL Server on master.

I am adding a check for case-insensitive quoted identifiers to the test that will work to skip the test on database that store case-insensitive identifiers as lower-case or upper-case. It will not work for databases that store case-insensitive identifiers as mixed-case (like SQL Server).

Those databases that store case-insensitive identifiers in mixed-case will need to be skipped explicitly, like is already done for SQL Server.

This is a test-only fix. Fixed in 5.1 branch by this commit: https://github.com/hibernate/hibernate-orm/commit/013daa2ca919ca3241088ac6d7b2f22a87d8e2e7