After llvm22, libxml2 needs to be provided by the host instead of the hermetic tool chain

*Title*: After llvm22, libxml2 needs to be provided by the host instead from the hermetic tool chain

*Description*:
when synced past #46371 , we start seeing link error requesting libxml2. Is this expected? Should the hermetic tool chain carry `libxml2` instead?

*Repro steps*:
On a host without `libxml2` installed, just bazel build any thing with `--config=clang`.

No source file or test is named. First reproduce the failure on a host without libxml2 with `bazel build` and `--config=clang`, then inspect the hermetic tool chain and the changes after LLVM 22. Done means the expected libxml2 dependency behavior is established and the reported build no longer fails under the documented host condition.

Written by the indexing model from the issue text.