False Negative: ConstantExpAppearsNonConstant.ql misses expressions that stay constant after trivial local rewrites.

Version
codeql 2.24.3

## Checker
- Checker id: `Likely Bugs/Arithmetic/ConstantExpAppearsNonConstant.ql`
- Checker description: This checker detects expressions that always evaluate to the same constant value but are not recognized as compile-time constants by the compiler, often due to containing non-constant sub-expressions that don't affect the final result.

## Description of the false negative
These cases still reduce to a constant result at runtime. One multiplies by zero. The others use `true || condition`, which is still always true regardless of the non-constant boolean input.

The only change is that the constant-looking behavior is expressed through locals or a slightly different spelling.

## Affected test cases
### `PosCase1.java`
`nonConstant * 0` still evaluates to zero regardless of the non-constant operand.

### `PosCase3_Var1.java` and `PosCase3_Var2.java`
Both variants are still logical constants. `Boolean.TRUE || condition` and `alwaysTrue || condition` should both be recognized as always true.

## Cause analysis
This looks like a propagation gap. `Likely Bugs/Arithmetic/ConstantExpAppearsNonConstant.ql` appears to lose the constant result once the expression is one step less direct, even though the same algebraic reasoning still applies.

That makes the query miss a kind of bug it should be well suited to catch.

## Reproduction code
### `PosCase1.java`
```java
// Multiplication by zero with integer literal zero operand should be flagged as always evaluating to zero.
package scensct.core.pos;

public class PosCase1 {
public PosCase1() {
int nonConstant = getNonConstant(); // Non-constant subexpression
int result = nonConstant * 0; // Multiplication by zero, always zero
// Use result in a conditional to emphasize constant evaluation
if (result == 0) {
// This branch is always taken
System.out.println("Always zero");
}
}

private int getNonConstant() {
return (int) (Math.random() * 100); // Non-constant value
}
}
```

## References
None known.

Likely Bugs/Arithmetic/ConstantExpAppearsNonConstant.ql から始め、ローカル変数と書き換えられた式を通じて定数の結果をどのように伝播させているかを調べてください。影響を受ける例として PosCase1.java、PosCase3_Var1.java、PosCase3_Var2.java を確認してください。クエリが説明されている定数式を認識し、既存の検出動作を失わなければ完了です。

索引モデルが issue の本文から書いたものです。