Removes MDC constants and unneeded angular package configs from packages.bzl.
Removes partial-compilation-integration from the karma web test tags because we don't perform any of partial compilation integration tests for devtools.
Some tooling was brought in from angular/components to help with bundling spec files for Karma. This tooling has since been ported over to the dev-infra repo. This commit dedupes the tooling and instead depends on the angular/dev-infra-private repo.
