This PR adds a failing regression test for issue #4308(Closed as duplicate). -> Fixes #4302

Summary

On H2 2.4.240, an INSERT that uses:

• a CHECK (col IN (...)) constraint, and
• DEFAULT on an IDENTITY primary key,
  fails only when executed across different connections/sessions.

The same SQL succeeds on:

• H2 2.3.232, and
• a single-connection workflow on 2.4.240.

Test

TestBug4308 (new)
reproduces the regression with plain JDBC using multiple connections.

The test is expected to fail on 2.4.240 and pass on 2.3.232.

Pass/Fail toggles observed

• Works if the CREATE TABLE connection is kept open (single-session).
• Works on H2 2.3.232.
• Works if the CHECK constraint is removed.
• Works if INSERT is executed on the same connection as CREATE TABLE.

Notes

• The test avoids Java text blocks for Java 11 compatibility.
• This PR intentionally makes CI red to capture the regression.
  A follow-up PR will provide a fix and turn CI green.