[2/2] Implement Unicode Normalization Form Quick Check (NF QC)

Use QuickCheck data from DerivedNormalizationProps.txt to check
if the input text is already in the desired Normalization Form.
\sa http://www.unicode.org/reports/tr15/#Detecting_Normalization_Forms

Using NF QC makes a significant boost to most operations that rely on
normalized input data, i.e. file path conversions on Mac, where "native"
form is a decomposed Unicode string.

Change-Id: I292a9da479c6beed730528fc7000c45bf1befc34
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
QLocale: Minor code dde-uplication

Change-Id: Ie48111a8f76798eb706d6a4036c7965d32ed542b
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Don't allocate QGlyphLayout data, when possible

...and operate directly on a passed array pointers,
without having to copy the input and output data.

Calling QFontEngine:: stringToCMap()/recalcAdvances() with
partially-constructed QGlyphLayout is completely safe
iff `glyphs` and `advances_?` members were initialized.

Also get rid of QGlyphLayoutInstance that was used just in a single place
and never was really needed.

Change-Id: I48fab246fd69fc869f948220a553c3574d93c772
Reviewed-by: Lars Knoll <lars.knoll@digia.com>