Use SAL_OVERRIDE consistently in CTLayout

When adding SAL_OVERRIDE to the member functions marked virtual, I
found one that was not an override of anything, and actually not used
at all: GetGlyphOutlines().

Change-Id: I3e56caa6262b2f21f7f47e3851ab0e07bbc4b642
fdo#64957: #i124233# prevent the accumulation of rounding errors

in CTLayout::FillDXArry()

Change-Id: I8ee83068d71275874e4af364df253251dfb41c8c