Fix SQL clause parsing and stabilize tests

[warny]

Motivation

• Recent refactor changed how SQL clauses were consumed and broke several SQL parsing tests due to clauses not being recognized or statement boundaries not respected.
• Parsing of DML statements (SELECT/INSERT/UPDATE/DELETE) needed to correctly capture initial clause content and then read remaining parts in order.
• Rebuilding SQL for DELETE sometimes emitted duplicate/misplaced targets when OUTPUT was present and needed normalization.
• A flaky test server in OData generator tests could throw when the listener was disposed during teardown.

Description

• Updated statement parsers (SelectStatementParser, InsertStatementParser, UpdateStatementParser, DeleteStatementParser) to first capture the initial clause using the part reader and then call ReadSegments to parse following clauses, passing ClauseStart.StatementEnd as a terminator.
• Modified StatementParserBase.ReadSegments to provide clause terminators (including StatementEnd) to part readers so readers stop at statement end.
• Adjusted clause part readers in SqlStatementPartReaders.cs to explicitly consume their leading keywords via TryConsumeSegmentKeyword and to handle empty results (e.g., DeletePartReader returns null when no target tokens were read).
• Made SqlQueryAnalyzer.Parse strip a pair of surrounding quotes for certain quoted inputs and updated SqlQuery/SqlDeleteStatement binding/output logic so DELETE output formatting avoids duplicate target text when equal to the FROM expression.
• Made the OData test helper tolerate disposed HttpListener errors by catching ObjectDisposedException alongside HttpListenerException in ServeCompressedMetadataAsync.

Testing

• Ran the full test suite with mise exec dotnet@9.0.100 -- dotnet test Utils.sln under .NET 9.
• Test results: all tests in the suite passed after fixes (0 failed, 645 passed, 6 skipped).
• Verified focused runs for previously failing tests (OData generator and NNTP client/server) to ensure stability.
• Build/pack steps invoked during dotnet test completed without errors (packages created as part of the solution build).

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Codex Task