do not build cargo-miri by default on stable channel

miri skipped for stable channel by default, do the same for `cargo-miri`.

Signed-off-by: onur-ozkan <[email protected]>

Author: onur-ozkan

src/bootstrap/src/core/build_steps/tool.rs

@@ -1096,7 +1096,7 @@ tool_extended!((self, builder),
     CargoClippy, "src/tools/clippy", "cargo-clippy", stable=true;
     Clippy, "src/tools/clippy", "clippy-driver", stable=true, add_bins_to_sysroot = ["clippy-driver", "cargo-clippy"];
     Miri, "src/tools/miri", "miri", stable=false, add_bins_to_sysroot = ["miri"];
-    CargoMiri, "src/tools/miri/cargo-miri", "cargo-miri", stable=true, add_bins_to_sysroot = ["cargo-miri"];
+    CargoMiri, "src/tools/miri/cargo-miri", "cargo-miri", stable=false, add_bins_to_sysroot = ["cargo-miri"];
     Rls, "src/tools/rls", "rls", stable=true;
     Rustfmt, "src/tools/rustfmt", "rustfmt", stable=true, add_bins_to_sysroot = ["rustfmt", "cargo-fmt"];
 );