Release of Ignite for JDK 21 usage

Hi all, I am a maintainer with the Trino project https://trino.io/ and we are currently very close to upgrade to support the upcoming JDK 21. The last issue is the JDBC driver used in our Apache Ignite connector. We sent a PR to fix one minor signature issue (https://github.com/apache/ignite

Re: IgniteTxStateImpl's non-threadsafe fields may cause crashes and/or data loss

Folks, idea to synchronize all methods unfortunately failed :( 1) TxState has 4 implementations, a lot of changes are required 2) IgniteTxEntry is not synchronized as well ... 3) And even IgniteInternalTx implementations (1+ lines) are not synchronized as well ... It seems to be unreal to refac