clap: Fix tests on non-Linux after the clap update

Author: LingMan

tests/cmd/h.stdout

@@ -15,7 +15,7 @@ Options:
                                 (YYYY-MM-DD), git tag name (e.g. 1.58.0) or git commit SHA.
       --force-install           Force installation over existing artifacts
   -h, --help                    Print help information (use `--help` for more detail)
-      --host <HOST>             Host triple for the compiler [default: x86_64-unknown-linux-gnu]
+      --host <HOST>             Host triple for the compiler [default: [..]]
       --install <INSTALL>       Install the given artifact
       --preserve                Preserve the downloaded artifacts
       --preserve-target         Preserve the target directory used for builds

tests/cmd/help.stdout

@@ -35,7 +35,7 @@ Options:
       --host <HOST>
           Host triple for the compiler
 
-          [default: x86_64-unknown-linux-gnu]
+          [default: [..]]
 
       --install <INSTALL>
           Install the given artifact