[SPARK-6550][SQL] Use analyzed plan in DataFrame

This is based on bug and test case proposed by viirya.  See #5203 for a excellent description of the problem.

TLDR; The problem occurs because the function `groupBy(String)` calls `resolve`, which returns an `AttributeReference`.  However, this `AttributeReference` is based on an analyzed plan which is thrown away.  At execution time, we once again analyze the plan.  However, in the case of self-joins, each call to analyze will produce a new tree for the left side of the join, rendering the previously returned `AttributeReference` invalid.

As a fix, I propose we keep the analyzed plan instead of the unresolved plan inside of a `DataFrame`.

Author: Michael Armbrust <michael@databricks.com>

Closes #5217 from marmbrus/preanalyzer and squashes the following commits:

1f98e2d [Michael Armbrust] revert change
dd4dec1 [Michael Armbrust] Use the analyzed plan in DataFrame
089c52e [Michael Armbrust] WIP