The sample locations were reordered "for fragment offset
computation". The reordering was causing some sample location tests
to fail.

Fixes SwANGLE tests:
dEQP.GLES31/functional_texture_multisample_samples_*_sample_position

Bug: b/147387937 b/139793135
Change-Id: I1a62d96517f2be0d625b9e9f8082d6f9e4c6a3f2
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/40508Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>