patch 9.1.0124: display of below/right virtual text with non-virtual text overlap

patch 9.1.0124: display of below/right virtual text with non-virtual text overlap

Problem:  Virtual text with text_align 'right'/'below' wasn't being
          used when a non-virtual text property overlaps with the end of
          the line. This was because the non-virtual text property had a
          higher priority, preventing the virtual text from being used.
Solution: Fix the sorting of text properties so virtual text properties
          have a higher priority than non-virtual text properties.
          (Dylan Thacker-Smith)

related: #14063

Signed-off-by: Dylan Thacker-Smith <dylan.ah.smith@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>