Improve output on test failures

Improve output on test failures

This adds checks to ensure Q_ALIGNOF is returning the desired alignment
for explicitly-aligned types.

The alignment check is now inlined in the test inside QCOMPARE so we get
slightly more informative errors:

FAIL!  : tst_Collections::alignment() Compared values are not the same
   Actual   (quintptr(&it.value()) % Value::PreferredAlignment): 64
   Expected (quintptr(0)): 0
   Loc: [tst_collections.cpp(3384)]

In this case, this is enough to notice "non-native" alignments are being
requested. Having test parameters otherwise hidden in template arguments
doesn't help the situation.

Change-Id: I05267fd25b71f183cfb98fb5b0a7dfd6c28da816
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>