Make Core Lint check for un-saturated type applications

Un-saturated type-family and type-synonym applications are
detected in the front end, but for some reason Lint wasn't
looking for them.

I came across this when wondering why Trac #9433 didn't give
a Core Lint error

(cherry picked from commit 8ff4671422090acf9146e3a90dd38e2c6f72aebb)
Check for un-saturated type family applications

This patch corrects an egregious error introduced by:

  commit 022f8750edf6f413fba31293435dcc62600eab77
  Author: Simon Peyton Jones <simonpj@microsoft.com>
  Date:   Thu May 15 16:07:04 2014 +0100

    Refactoring around TyCon.isSynTyCon

    * Document isSynTyCon better
    * Add isTypeSyonymTyCon for regular H98 type synonyms
    * Use isTypeSynonymTyCon rather than isSynTyCon where
      the former is really intended

At this particular spot in TcValidity we really do mean
isSynTyCon and not isTypeSynonymTyCon.

Fixes Trac #9433

(cherry picked from commit ee4501bbad6480509e8a60b5ff89c0b0b228b66d)

Conflicts:
	testsuite/tests/indexed-types/should_fail/all.T