Same fix as e70d7a2a7c
This is because the CompilerOptions needs to have directoryExists undefined in order to get the google3 behavior,
so we have to set the property outside the constructor.
Fixes#21872
PR Close#21876
Add enough BUILD files to make it possible to
`bazel build packages/core/test`
Also re-format BUILD.bazel files with Buildifier.
Add a CI lint check that they stay formatted.
PR Close#20768