Previously faux bold was drawn with setting a dictionary key
kCTStrokeWidthAttributeName and a value of the stroke width. This
stopped working because we don't use attributedString for drawing
anymore but we always use CTFontDrawGlyphs and draw the glyphs,
which doesn't have a way to set this attributes.

It took me a while to find a workaround (thanks to Apple's great
documentation), where we switch text drawing to fill and stroke,
and after that we can modify the stroke by changing the line
width.

Change-Id: I594fcb9c796a9c04ea8234a9938ca2f719706199
Reviewed-on: https://gerrit.libreoffice.org/71012
Tested-by: Jenkins
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>