IGNITE-28102 Jdbc. Fix client observable timestamp skew in multistatement query cases

[solveme]

• Attach HybridTimestampTracker from initial query request (can be refered as parent HTT) to each ongoing result set fetch requests, thus the client's observed timestamp is constantly updated.
• Add stricter result set checks and assertions to affected flaky test

https://issues.apache.org/jira/browse/IGNITE-28102

[Copilot]

Pull request overview

This PR addresses observable timestamp skew for thin-client SQL multi-statement flows by propagating the original request’s HybridTimestampTracker across subsequent “next result set” fetches, and hardens a flaky JDBC multi-statement integration test via stricter result validation utilities.

Changes:

• Propagate the “parent” HybridTimestampTracker from SQL_EXEC through saved next-result resources and apply it when handling SQL_CURSOR_NEXT_RESULT_SET.
• Introduce reusable JDBC test-fixture helpers (StatementResultCheck, RowColumnProjection, RowsProjectionMatcher) to assert multi-statement results precisely.
• Refactor ItJdbcMultiStatementSelfTest.testMixedDmlQueryExecute to validate each result/update count explicitly.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
modules/jdbc/src/testFixtures/java/org/apache/ignite/jdbc/util/StatementResultCheck.java	Adds a small DSL for asserting Statement results across getMoreResults() iterations.
modules/jdbc/src/testFixtures/java/org/apache/ignite/jdbc/util/RowsProjectionMatcher.java	Adds Hamcrest matchers for projected result-set row values (order-sensitive / insensitive).
modules/jdbc/src/testFixtures/java/org/apache/ignite/jdbc/util/RowColumnProjection.java	Adds a projector utility to drain a ResultSet into a list of extracted values.
modules/jdbc/src/integrationTest/java/org/apache/ignite/jdbc/ItJdbcMultiStatementSelfTest.java	Replaces a coarse result-size assertion with strict per-result assertions for a mixed DML/query script.
modules/client-handler/src/main/java/org/apache/ignite/client/handler/requests/sql/ClientSqlExecuteRequest.java	Passes the request timestamp tracker into result-set writing so it can be propagated to next-result resources.
modules/client-handler/src/main/java/org/apache/ignite/client/handler/requests/sql/ClientSqlCursorNextResultRequest.java	Reads the stored “parent” tracker and updates the current request tracker from it before writing the result.
modules/client-handler/src/main/java/org/apache/ignite/client/handler/requests/sql/ClientSqlCommon.java	Stores parentTsTracker alongside next-result cursor futures (via NextCursorContext).
modules/client-handler/src/main/java/org/apache/ignite/client/handler/ClientInboundMessageHandler.java	Updates call site for the modified ClientSqlCursorNextResultRequest.process(...) signature.

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