Don't construct queries with too many OR statements for SQLite

[mcserep]

#801 improved the performance for Lack of Cohesion metric, by refactoring 3 level nested query loop to 2 level.

However, SQLite has a fixed-size recursive descent parser, and each logical operator (like OR) adds a level to the parser's stack. Constructing queries with many ORs can lead to a stack overflow.

[Copilot]

Pull Request Overview

This PR addresses SQLite's recursive descent parser limitation by implementing conditional compilation to handle large OR queries that can cause stack overflow. The change splits the Lack of Cohesion metric calculation into two approaches: a safer iterative approach for SQLite and an optimized query-based approach for more robust database engines.

• Added conditional compilation (#ifdef DATABASE_SQLITE) to use different query strategies based on database type
• Moved field counting outside the conditional blocks for code reuse
• Implemented a simpler query approach for SQLite that avoids constructing queries with many OR statements

Comments suppressed due to low confidence (1)

plugins/cpp_metrics/parser/src/cppmetricsparser.cpp:410

• The fieldCount variable declaration was moved outside the conditional blocks but is still being removed from the non-SQLite branch. This creates duplicate variable declarations since fieldCount is now declared at line 318. Remove this duplicate declaration.

        // Counter variables.