Improve transaction handling in Prism Driver & Decimal validation

[gartens]

The main contribution of this PR are improvements to transaction handling in the Prism driver and decimal validation:

• Ensure that statements objects used in the Prism driver belong to the current transaction (with a test that would have exposed this)
• Ignore leading 0 in decimal number validation to match the documentation
• Throw an exception when trying to create a statement for an inactive transaction (this exposed an issue in anyPrepareQuery)
• Improve type derivation in prepared statements
• Replace a few subtractions with the more appropriate Integer.compare

[vogti]

Thx, @gartens and @datomo, for this PR!