reporting

Signed-off-by: Paul Merlin <paul@gradle.com>

Android 2.3 uses the internal DurationFormatter class for its

test reporting. This has been fixed in Android 3.0, but we want

to keep Android 2.3 working a while longer. We will remove this

class in Android 5.0

This adds coverage for reporting on connected tests (the scenario that

broke). It does not add coverage for actually running the tests, since

that would require additional setup like an emulator.

This also adds coverage for Android 3.0 to ensure we don't break the

latest beta.

* Don't make TimeProvider Serializable.

This isn't safe and generally doesn't make sense.

* Extract and promote the concept of a build timer.

This was previously not well defined and being overlaid with the concept of when a user/tool requested something, which is not always the same thing.

* Pare down the deprecated org.gradle.util.Clock down to the minimum required.

Internal usage is replaced by a `getStartTime()` directly on BuildRequestContext.

What is left is only kept for backwards compatibility with scans.

* Rename TimeProvider to Clock.

* Move BuildExecutionTimer out of baseServices into core, and into a better package.

* Remove unused.

* Simplify the time package by merging types.

* Prevent the client's build started timestamp from being later than when the provider received the build request.

* Provide a dedicated mechanism for conveying the build start time to build scans.

* Consolidate the ways of formatting durations.