Fix non-determinism in rules_rs/crate_git_repository.bzl (#16590)

Running multiple builds with no changes causes some differences, we see
that
https://app.buildbuddy.io/compare/a9719629-1660-4735-a477-d66357f234fb...df85310b-eb5c-4c10-8b79-4d0449ba6cdd#file
shows the file-differences between two Bazel builds.

These differences are caused by a non-deterministic `.git` entry in the
rules_rs crates that are created with `crate_git_repository`.

As a way to make these deterministic, we can remove this entry after we
download the git source, so that the input to the compile action is
deterministic.

### CLA

I have read the CLA Document and I hereby sign the CLA

patches/rules_rs_delete_git_worktree_pointer.patch

@@ -0,0 +1,20 @@
+diff --git a/rs/private/crate_git_repository.bzl b/rs/private/crate_git_repository.bzl
+--- a/rs/private/crate_git_repository.bzl
++++ b/rs/private/crate_git_repository.bzl
+@@ -35,6 +35,14 @@
+         "HEAD"
+     ])
+     if result.return_code != 0:
+         fail(result.stderr)
+
++    # Remove .git worktree pointer file. It contains an absolute path to
++    # the bazel output base which is machine-specific and non-deterministic.
++    # Leaving it in pollutes compile_data globs and causes AC misses.
++    #
++    # Note that bazelbuild/rules_rust ignores .git (among other paths) during splicing:
++    # https://github.com/bazelbuild/rules_rust/blob/ca4915c0210bcd240152a5333ecb24d266bda144/crate_universe/src/splicing/splicer.rs#L42
++    rctx.delete(root.get_child(".git"))
++
+     if strip_prefix:
+         dest_link = dest_dir.get_child(strip_prefix)
+         if not dest_link.exists: