Use SAL_FINAL here

Sure, not that useful in this case (where it is quite obvious anyway
that the class is not derived from), but just to verify that the
SAL_FINAL thing works.

Change-Id: Icef6eb64e278354694145bf98f02b9ffe5db7da7

vcl/coretext/salcoretextlayout.cxx

@@ -30,7 +30,7 @@
 #include "headless/svpgdi.hxx"
 #endif
 
-class CoreTextLayout : public SalLayout
+class CoreTextLayout SAL_FINAL : public SalLayout
 {
 public:
     CoreTextLayout( QuartzSalGraphics* graphics, CoreTextStyleInfo* style);