SwiftSyntax 603.0.1 passes build but breaks expression macro compiler-plugin arguments under Apple Swift 6.3.1

### Description

## Description

Expression macro compiler-plugin tests that pass with SwiftSyntax 602.0.0 fail with SwiftSyntax 603.0.1 under Apple Swift 6.3.1.

The package builds successfully with 603.0.1, but compiler-plugin expansion tests fail as if the freestanding expression macro invocation arguments are missing or malformed.

## Environment

- macOS:
- Xcode: 26.4.1
- Swift: Apple Swift version 6.3.1
- swift-driver: 1.148.6
- SwiftSyntax passing version: 602.0.0
- SwiftSyntax failing version: 603.0.1
- SwiftSyntax 603.0.1 revision observed: 9de99a78f099e59caf2b2beec65a4c45d54b2081

## Reproduction

Using this package:

https://github.com/naykutguven/ConcurrencyMacros

Change the SwiftSyntax dependency from the verified 602 range to 603:

```swift
let swiftSyntaxRange = Version(603, 0, 0)..