Revert "cloud.clouds.ec2: cache each named node (#33164)"

This reverts commit b3805d825a ("cloud.clouds.ec2: cache each named
node (#33164)").

Commit 25771fc030 ("_get_node return instance info directly, not a
dict of instances") from 2016.3 feature release changed how the result
of _get_node should be interpreted. Before it was like

  res = _get_node(...)
  node = res[name]

and after the commit it became

  node = _get_node(...)

Commit b3805d825a ("cloud.clouds.ec2: cache each named node (#33164)")
submitted into 2015.8 as a bugfix for #33162 added loops over the keys
of a dictionary returned by _get_node, fixing
salt.utils.cloud.cache_node calls in queue_instances() and
show_instance().

But after being merged into 2016.3 with merge commit 679200aeb2
("Merge branch '2015.8' into '2016.3'"), the commit in question
reintroduced the bug on 2016.3 because of changed return value of
_get_node.

Fixes #39782

salt/cloud/clouds/ec2.py

@@ -2647,11 +2647,7 @@ def queue_instances(instances):
     '''
     for instance_id in instances:
         node = _get_node(instance_id=instance_id)
-        for name in node:
-            if instance_id == node[name]['instanceId']:
-                __utils__['cloud.cache_node'](node[name],
-                                            __active_provider_name__,
-                                            __opts__)
+        __utils__['cloud.cache_node'](node, __active_provider_name__, __opts__)
 
 
 def create_attach_volumes(name, kwargs, call=None, wait_to_finish=True):
@@ -3200,10 +3196,7 @@ def show_instance(name=None, instance_id=None, call=None, kwargs=None):
         )
 
     node = _get_node(name=name, instance_id=instance_id)
-    for name in node:
-        __utils__['cloud.cache_node'](node[name],
-                                    __active_provider_name__,
-                                    __opts__)
+    __utils__['cloud.cache_node'](node, __active_provider_name__, __opts__)
     return node