[bazel] Add subpackages for libc/hdr/... (#242520)
This PR creates subpackages for `libc/hdr/...` as part of
https://github.com/llvm/llvm-project/issues/238076.
The refactor was entirely generated by a one-off tool
[jtstogel/bazel-move-targets](https://github.com/jtstogel/bazel-move-targets)@1e51f7f
(LLM-written), since AFAICT there's no good standard tooling for this
kind of thing.
Generated by:
```
function new-pkg() {
pkg=$1
shift
bazel-move-targets move \
--workspace_root=utils/bazel/llvm-project-overlay \
--src_package=libc \
--dst_package=$pkg \
"${@}"
jj commit -m "[bazel] Add subpackage for $pkg"
}
new-pkg libc/hdr/types --rename_strip_package_prefix=types_
new-pkg libc/hdr/func --rename_strip_package_prefix=func_
new-pkg libc/hdr --rename_strip_package_prefix=hdr_
```
