[llvm] [AsmPrinter] Simplify $local after D131429. NFC (PR #128138)

[Fangrui Song via llvm-commits]

MaskRay wrote:

> Similarly, I wonder if we could change all the guarded `OutStreamer->emitELFSize` to just `OutStreamer->emitSymbolSize()` and make that a non-op on unsupported platforms. The emitELFSize() appears to be misnamed since e.g. WASM also sets the size.

Thanks for the suggestion. Let me explore this as a potential simplification...

https://github.com/llvm/llvm-project/pull/128138