Fix Swift find_referencing_symbols: add --scratch-path and resolve via xcrun#1166

Asher- wants to merge 2 commits intooraios:mainoraios/serena:mainfrom

Asher-:fix/sourcekit-lsp-scratch-path-and-xcrunAsher-/serena:fix/sourcekit-lsp-scratch-path-and-xcrunCopy head branch name to clipboard