[cairo] Testsuite changes this week

[Bryce W. Harrington]

                  git     git       git
                  05/03   05/12   06/09
---------------------------------------
Tests run:        24838   24838   24813
Passed:           15774   15743	  16015
Failed:            6476    6505	   6226 
Expected Failed:    332     332	    315	 
Error:                1       0	      1	 
Crashed:             32      35	     33	 
Untested:          2223    2223	   2223 
Total:            24838   24838	  24813

The revert of the downscaling patch likely accounts for the jump in test
passes, however of course the downscale tests now are failing (since
they were calibrated to results with the downscale patch); possibly we
should mark those tests as expected fails now, but not sure.  In any
case that represents 93 tests that were passing that now fail.

There are also 19 pthread tests which were passing that now fail, but
I'm skeptical if these are real failures.  It seems we always have
irregularities in the results with the threading tests...

Aside from downscale and pthread tests, these three tests also switched
from pass to fail on these two test runs:

PASS -> FAIL # bitmap-font.gl-window.argb32
PASS -> FAIL # degenerate-path.gl-window.argb32
PASS -> FAIL # pass-through.gl-window.argb32

It's interesting all three are with the gl-window backend, but otherwise
the three tests have little commonality.  It's not evident looking at
the test code why they'd be failing, and nothing in the git logs pops
out as directly relating to gl-window.  Anyone else seeing these three
tests failing now, but passing as of a month ago?

Bryce