Weston test suite colors are wrong on llvmpipe
After commit 4e2d8878 the Weston test suite no longer passes on llvmpipe.
Tests that used to have a blue background now have a reddish one - but I'm not certain this is just a swizzle, it may be that floating point values aren't being treated as such.
The background color in these tests is a solid color provided by a uniform variable. Textured content in the tests appears as expected.