Bazel: DPC++ tests/examples cannot be analyzed in release link modes -- @onedal_release//:onedal_static_dpc does not exist #3791

_get_dpc_deps in dev/bazel/dal.bzl builds a DPC++ target's dependencies by appending _dpc to every entry of dal_deps. For tests and examples, dal_deps comes from _test_link_mode_deps, which is a select over the link mode:

def _test_link_mode_deps(dal_deps, use_onedal_release_libs=True):
    return _select({
        "@config//:test_link_mode_dev": dal_deps,
        "@config//:test_link_mode_release_static":  ["@onedal_release//:onedal_static"],
        "@config//:test_link_mode_release_dynamic": ["@onedal_release//:onedal_dynamic"],
    })

So a DPC++ target in release_static mode asks for @onedal_release//:onedal_static_dpc, and neither dev/bazel/deps/onedal.tpl.BUILD nor dev/bazel/deps/onedal_win.tpl.BUILD declares such a target. Measured on Linux, main, against a Bazel-built release:

$ bazel cquery 'filter(":onedal_", deps(//examples/oneapi/dpc:_basic_statistics_dense_batch_dpc))' \
      --test_link_mode=release_static
ERROR: .../external/+onedal_repo+onedal_release/BUILD: no such target
  '@@+onedal_repo+onedal_release//:onedal_static_dpc': target 'onedal_static_dpc' not declared
  ... and referenced by '//examples/oneapi/dpc:_basic_statistics_dense_batch_dpc'
ERROR: Analysis of target '//examples/oneapi/dpc:_basic_statistics_dense_batch_dpc' failed

The same query in release_dynamic mode resolves, because onedal_dynamic_dpc happens to exist:

$ bazel cquery 'filter(":onedal_(dynamic|static)", deps(//examples/oneapi/dpc:_basic_statistics_dense_batch_dpc))' \
      --test_link_mode=release_dynamic
@onedal_release//:onedal_dynamic_dpc (431669a)

CI does not notice because no job builds a DPC++ test or example in a release link mode. The release-mode example steps in .ci/pipeline/ci.yml are //examples/daal/cpp:all and //examples/oneapi/cpp:all, and neither package contains a _dpc cc_test/cc_binary target — the only dpc-named entries there are the example_util_dpc header module. //examples/oneapi/dpc:all (94 targets) is never built in release_static or release_dynamic by any pipeline.

Two ways out, and I have no opinion strong enough to pick without a maintainer:

1. Declare the missing release targets (onedal_static_dpc, and on Windows the DPC import library/DLL in onedal_repo first) so that DPC++ tests and examples can genuinely link against a release.
2. Make the release-mode dependency selection non-DPC-aware, i.e. do not _dpc-mangle labels that come from _test_link_mode_deps, so DPC++ targets in release modes link the host release libraries deliberately rather than by accident.

Either way it would be worth adding a //examples/oneapi/dpc:all --test_link_mode=release_dynamic step, otherwise the configuration stays untested whichever fix lands.

Found while reviewing feedback on #3790, which removes the Windows onedal_dynamic_dpc stub; that target is unreachable in every configuration CI exercises, and this issue is the reason the asymmetry existed in the first place.