gh-71956: Fix IDLE Replace All searching up without wrap around (#152737)

gh-71956: Fix IDLE Replace All searching up without wrap around (#152737)

When the search direction is "Up" and "Wrap around" is off, Replace All
replaced only the first match above the current position (and all matches
below it).  It now replaces all matches from the start of the text down to
the current position, consistently with the "Up" direction.