[Spark-4509] Revert EC2 tag-based cluster membership patch

This PR reverts changes related to tag-based cluster membership. As discussed in SPARK-3332, we didn't figure out a safe strategy to use tags to determine cluster membership, because tagging is not atomic. The following changes are reverted:

SPARK-2333: 94053a7b766788bb62e2dbbf352ccbcc75f71fc0
SPARK-3213: 7faf755ae4f0cf510048e432340260a6e609066d
SPARK-3608: 78d4220fa0bf2f9ee663e34bbf3544a5313b02f0.

I tested launch, login, and destroy. It is easy to check the diff by comparing it to Josh's patch for branch-1.1:

https://github.com/apache/spark/pull/2225/files

@JoshRosen I sent the PR to master. It might be easier for us to keep master and branch-1.2 the same at this time. We can always re-apply the patch once we figure out a stable solution.