Fix zombie XA connection after deadlock by deferring closeTxConnections

[dixitdeepak]

closeTxConnections() was called at the top of rollback() and commit(), before ut.rollback()/ut.commit().

When MySQL auto-rolled back an XA branch due to a deadlock (XA_RBDEADLOCK), BTM attempted XA END on the connection during close(), failed silently, and lost track of the XA resource. The connection was then returned to the pool with an unresolved ROLLBACK_ONLY XA branch still open in MySQL.

The next thread to acquire that connection received XAER_RMFAIL on XA START.

The fix removes the premature closeTxConnections() calls from both methods. clearCurrent() in the finally block already calls closeTxConnections() as a safety net — it now becomes the sole caller, always running after the JTA operation completes and the XA lifecycle (XA END + XA ROLLBACK/COMMIT) has been properly finalized on all enlisted resources. suspend() is unaffected as it intentionally closes connections before suspending.

[dixitdeepak]

Previously, transaction connections could be closed before UserTransaction.rollback() was executed. This creates a risk that resources participating in the transaction are released before the transaction manager completes rollback processing, particularly in failure scenarios where the resource manager has already reported an error.

This change ensures that:

1. UserTransaction.rollback() is executed first.
2. Transaction-scoped connections and resources are cleaned up only after rollback processing completes.

This ordering allows the transaction manager to properly complete rollback processing on all enlisted resources before they are released, reducing the risk of resource state inconsistencies and subsequent transaction enlistment failures when connections are returned to and later reused from the pool.