Ensure that GA modules don't depend on beta functionality

[morgante]

We should remove the beta provider from the testing config for the non-beta modules and ensure that it's not required.

[kopachevsky]

@aaron-lane @morgante examples/node_pool uses node_config taint property, that in Beta

terraform-google-kubernetes-engine/examples/node_pool/main.tf

Lines 92 to 99 in 1ce3e62

	node_pools_taints = {
	all = [
	{
	key = "all-pools-example"
	value = true
	effect = "PREFER_NO_SCHEDULE"
	},
	]

How do we proceed with this example and corespondent test? create new node_pool that uses modules/beta_public, keep one node_pool but move it to beta fully or just remove taints part from example/test?

[nick4fake]

@kopachevsky I suggest simply pointing that example to the beta submodule
@morgante what should we do with the fact of taints missing from non-beta provider?

[morgante]

We can move that example to point to the beta provider.