[BEAM-1871] Move GCP specific serialization CloudObject and supporting translation code to Dataflow runner module

[lukecwik]

Be sure to do all of the following to help us incorporate your contribution
quickly and easily:

• Make sure the PR title is formatted like:
  [BEAM-<Jira issue #>] Description of pull request
• Make sure tests pass via mvn clean verify.
• Replace <Jira issue #> in the title with the actual Jira issue
  number, if there is one.
• If this contribution is large, please file an Apache
  Individual Contributor License Agreement.

---

[lukecwik]

R: @dhalperi @kennknowles

[lukecwik]

Run Dataflow ValidatesRunner

[dhalperi]

Confirming: This is taking code that only DataflowRunner uses and either moving it into Dataflow module or deleted it entirely. Looks awesome to me!

[lukecwik]

@dhalperi That is correct.

[kennknowles]

So much deletion. So happy.

[coveralls]

Coverage increased (+0.6%) to 70.581% when pulling c85b29f on lukecwik:thin_sdk_core into f33039b on apache:master.

[lukecwik]

The build succeeded https://builds.apache.org/job/beam_PreCommit_Java_MavenInstall/10664 but reported failure to Jenkins because it was married with a build in 10665 which seems unrelated.

[lukecwik]

retest this please

[coveralls]

Coverage increased (+0.6%) to 70.581% when pulling c85b29f on lukecwik:thin_sdk_core into f33039b on apache:master.