IGNITE-26758: Figure out what qryResCache is used for and where it is used

[animovscw]

• As part of the qryResCache investigation, test-only instrumentation has been added: a hit counter in GridCacheQueryManager.executeFieldsQuery(...) + the resetExecuteFieldsQueryHitCount() / executeFieldsQueryHitCount() methods.
• Added a GridCacheQueryManagerExecuteFieldsQueryTest reproducer test, which verifies that executeFieldsQuery(...) is not called when executing a SqlFieldsQuery:
  • for local=true (including parallel execution in two threads),
  • and for local=false on two nodes with keys distributed across the primary nodes.

Result:

The counter remains 0, meaning executeFieldsQuery(...) is not involved in the SqlFieldsQuery execution path, and qryResCache is not involved in this scenario.