testing: remove old test reference output we no longer need (#4817)

Delete some reference test output for older toolchains and dependency
versions that seem no longer needed.

Signed-off-by: Larry Gritz <lg@larrygritz.com>

Author: lgritz

testsuite/oiiotool-text/ref/aligned-freetype2.4.11.tif

@@ -124,7 +124,7 @@ def oiio_app (app):
 if int(os.getenv('TESTSUITE_CLEANUP_ON_SUCCESS', '0')) :
     cleanup_on_success = True
 
-image_extensions = [ ".tif", ".tx", ".exr", ".jpg", ".png", ".rla",
+image_extensions = [ ".tif", ".tiff", ".tx", ".exr", ".jpg", ".png", ".rla",
                      ".dpx", ".iff", ".psd", ".bmp", ".fits", ".ico",
                      ".jp2", ".jxl", ".sgi", ".tga", ".TGA", ".zfile" ]