Use new cpubuilder dockerfile for ASan and TSan jobs.

[ScottTodd]

Following https://github.com/iree-org/base-docker-images/pull/6, the new cpubuilder dockerfile should have all the software needed for ASan and TSan building + testing (specifically clang-19 instead of just clang-14).

Progress on https://github.com/iree-org/iree/issues/15332. The only remaining uses of gcr.io/iree-oss/base.* are:

• build_test_all_bazel uses gcr.io/iree-oss/base-bleeding-edge
• publish_website uses gcr.io/iree-oss/base
• arm64 workflows use gcr.io/iree-oss/base-arm64
• gcr.io/iree-oss/emscripten (used by web test workflows) depends on gcr.io/iree-oss/base