fix: handle null operands in LogicOrOperator for consistency with && and !

[chenjunwenhao]

Summary

LogicAndOperator and LogicNotOperator both treat null as false, but LogicOrOperator throws INVALID_BINARY_OPERAND when either operand is null. This inconsistency causes null || true to fail at runtime while null && true correctly returns false and !null correctly returns true.

Problem

// These all work:
null && true   // → false
null && null   // → false
!null          // → true

// This throws INVALID_BINARY_OPERAND:
null || true   // Expected: true, Actual: error
null || null   // Expected: false, Actual: error

Fix

Add null-to-false conversion in LogicOrOperator.execute(), matching the pattern already used in LogicAndOperator and LogicNotOperator:

if (leftValue == null) {
    leftValue = false;
}
if (rightValue == null) {
    rightValue = false;
}

Tests

Added logic_or_null.ql test suite covering:

• || operator with null operands (left, right, both)
• or keyword with null operands
• Consistency with !null behavior

Changed Files

• src/main/java/.../runtime/operator/logic/LogicOrOperator.java — added null handling
• src/test/resources/testsuite/independent/operator/logic_or_null.ql — new test suite