Resolves: #i124935# fix expanded/condensed text breaking...

in the CoreText engine

the concept of an extra-width per code-unit was obsolete at least since apps
supported unicode with its different normalization forms, diacritical marks,
surrogate-pairs, non-printing characters such as ZWJ/ZWNJ/RLM, etc.  so of
course modern engines like CoreText don't aid this typographical crime.

The fix here extends the CTLayout::GetTextBreak() method to handle the obsolete
semantic of per code-unit extra-widths by successively approximating the number
of involved code-units.
(cherry picked from commit a9b9ceff86f35be1eeff5f251d24e338db760a1e)

Conflicts:
	vcl/aqua/source/gdi/ctlayout.cxx

Change-Id: I52a7f7488a9e8a303ed7271df2a24a3c85098ce3
(cherry picked from commit 687f0c9300d499b78deea2890b4c2019adb2d67d)
Reviewed-on: https://gerrit.libreoffice.org/9627
Reviewed-by: Christian Lohmaier <lohmaier+LibreOffice@googlemail.com>
Tested-by: Christian Lohmaier <lohmaier+LibreOffice@googlemail.com>