[Part 2] Integrate parameter filtering into RouteSQLRewriteEngine

[Fottas]

Overview

This is the second PR for the IN predicate optimization feature, integrating parameter filtering logic into RouteSQLRewriteEngine.

Changes

Modified RouteSQLRewriteEngine.java

• Enhanced getParameters() method to call parameter filtering
• Added filterParametersIfNeeded() method to detect and apply parameter filtering when ParameterFilterable tokens exist
• Added findParameterFilterableTokens() method to identify tokens implementing ParameterFilterable interface
• Added applyParameterFiltering() method to merge removed indices from multiple tokens and filter parameters

Added unit tests in RouteSQLRewriteEngineTest.java

• Test behavior when no filterable tokens exist
• Test single token parameter filtering
• Test multiple tokens with index merging
• Test parameter order preservation after filtering

Design Rationale

• Zero performance impact when no filterable tokens exist (only a simple list traversal)
• Supports multiple ParameterFilterable tokens with automatic index merging
• Preserves parameter order for remaining parameters
• Fully backward compatible - existing tokens continue to work without changes

Related Issue

Part of #36454

Next Steps

The next PR will introduce data structures (ShardingInPredicateValue and ShardingInPredicateToken) that utilize this parameter filtering infrastructure.

[terrymanu]

Right now the changes are spread across multiple PRs, which makes it hard to assess the overall design and impact. Please consolidate the main code into a single, complete PR so we can review the design, code, and tests together. Otherwise, each fragmented PR lacks context and cannot be merged.