Allow `DiffAwareness` to share precomputed information about the workspace and
propagate it to the `WorkspaceStatusAction`.

Each successful Bazel build issue 2 `BuildInfo` events -- one based on the
result of running the command indicated by `workspace_status_command` and a
dummy one based on a subset of available information. Receivers of those
discard all but the first one. If a build fails before execution phase, the
dummy event will be the only even issued, hence it will be used.

`DiffAwareness` operates on the workspace to figure out the diffs and in the
process probes properties of it. Allow `DiffAwareness` to share such
information with the intention to make it available for the rest of the build.

Propagate unanimous precomputed workspace information when it is available from
`DiffAwareness` through the `DiffAwarenessManager` and `SkyframeExecutor` to
`CommandEnvironment` and store it there to make it available for the rest of
the build.

Make precomputed workspace information available to the dummy `BuildInfo`
event.

PiperOrigin-RevId: 355072552