I looked into the texture size issue and I removed the " + Int(1)"
used on the LOD and replaced it with "baseLevel", which I think makes
more sense. Without the "+1", some tests using baseLevel==1 fail, but
all tests pass when I use "+baseLevel". I'm not 100% sure why the
"+1" wasn't making tests that were using baseLevel==0 fail.

Note that, for now, the new Sampler::State "baseLevel" member will
always be 0, as the code to set it hasn't landed yet and will be in
another cl.

Change-Id: I8532bb7009abcc15e03416489f1d25027e336457
Reviewed-on: https://swiftshader-review.googlesource.com/5471Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>