[Enhancement] Optimize JmsSelector method

[wizcraft_kris]

Before Creating the Enhancement Request

• I have confirmed that this should be classified as an enhancement rather than a bug/feature.

Summary

Remove dead code patterns in SelectorParser methods.

Motivation

• if (true) return patterns are redundant and misleading
• Unreachable throw statements clutter code and may cause static analysis warnings
• Cleanup improves code readability and maintainability

Describe the Solution You'd Like

• Fix all occurrences in these methods:
  orExpression()
andExpression()
equalityExpression()
literal()
stringLitteral()
variable()
• Direct return instead of if (true) return
• Remove unreachable throw new Error(...)

Describe Alternatives You've Considered

• Keeping redundant code with comments: Rejected as it retains technical debt.
• Repurposing the throw statement: Irrelevant since code is unreachable.

Additional Context

// Pattern to remove in all affected methods:
{
    if (true) return ...; // <- Remove wrapper
}
throw new Error(...);     // <- Dead code