[lldb][bytecode] Swift output is conditional on >=6.3 (#187544)
The `@section` and `@used` attributes are available in Swift 6.3 and
later. See [SE-0492][1].
Prior to 6.3, these were available as `@_section` and `@_used`, however
those require enabling the `SymbolLinkageMarkers ` experimental feature.
[1]: https://github.com/swiftlang/swift-evolution/blob/main/proposals/0492-section-control.md