Fix Statement.getUpdateCount: return -1 when current result is a ResultSet

[IceboxDev]

LibSqlStatement.getUpdateCount() currently returns rows_written unconditionally, including for SELECT queries where rows_written == 0.

Per the JDBC spec:

Retrieves the current result as an update count; if the result is a ResultSet object or there are no more results, -1 is returned.

Returning 0 instead of -1 for a SELECT means "an update result with 0 rows affected" ? a different, legitimate state. Clients that walk all results via the standard pattern loop forever:

do {
    val isRs = stmt.getMoreResults()
    val n = stmt.getUpdateCount()
    if (!isRs && n == -1) break
    // ...
} while (true)

This manifests in JetBrains DataGrip / PyCharm as the query showing rows in the editor but the "loading" spinner never stopping. Eventually the RMI proxy backing the Statement is GC'd on the driver side and the IDE log fills with java.rmi.NoSuchObjectException: no such object in table from UniversalResultsProducer$StatementSource.hasMoreResultSets / getUpdateCount.

Fix:

• getUpdateCount / getLargeUpdateCount return -1 when the current result is a ResultSet (signalled by executionResult.getColumns() being non-empty) or when there is no current result.
• getMoreResults() (both overloads) clears executionResult and resultSet so subsequent getUpdateCount correctly returns -1 for "no more results".
• Removed LibSqlException("No update count before statement execute") ? per spec, getUpdateCount returns -1 in that state, it does not throw.

[codacy-production]

Up to standards ✅

🟢 Issues 0 issues

Results:
0 new issues

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🟢 Metrics 4 complexity · 2 duplication

Metric	Results
Complexity	4
Duplication	2

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