Major Description
Problem
Consider the following scenario:
1) User's app started JVM in the process somehow.
2) User tries to start the node.
3) Result: exception.
Solution
We need to check if JVM is already started. If yes - then try re-using. Note that we are likely to fail at this point because user might forgot to pass proper Ignite classpath. In this case we must throw extremely sensible exception, so that user understand how to fix the problem right away.
E.g.: "Failed to start Ignite node with already started JVM due to invalid classpath; please add the following JARs to the classpath: [PATH TO IGNITE_HOME JARS]".