Ensure `--use` will select the toolchain#456

cmcgee1024 merged 1 commit intoswiftlang:mainswiftlang/swiftly:mainfrom

bkhouri:t/main/use_even-if-toolchain-is-already-installedbkhouri/swiftly:t/main/use_even-if-toolchain-is-already-installedCopy head branch name to clipboard