Regression test for GitHub issue 1391

[talkinnl]

Regresssion tests: Use the same Statement to insert a row with short strings first, and longer strings second.

• Issue also happens with VARCHAR( >=4002 ). Not just Max or NVARCHAR
• Issues 1391, 1393 (and possibly 1371 ?) might all have the same root cause.

[ghost]

All CLA requirements met.

[talkinnl]

Ok, I opened a new PR with 'dev' as base branch and the drop_table table name fixed: https://github.com/microsoft/msphpsql/pull/1404