Fix expectation for multisample SPIR-V test
Fix expectation for multisample SPIR-V test

The last subtest of the builtin variable decorations
SPIR-V test renders to a 2-sample multisample FBO by
clearing to black and then using a fragment shader
that uses gl_SampleMask to select only one of the 2
samples. The selected sample always outputs 100% green.

Because the sample locations can be different acrosss
implementations, we can't tell what the resolved green
component will be, only that it cannot be 0x00 (since
one green sample is selected) and it cannot
be 0xFF (since sample coverage is only 50%).

Modules: OpenGL

VK-GL-CTS issue: 850

Affects:
KHR-GL45.gl_spirv.spirv_validation_builtin_variable_decorations_test
KHR-GL46.gl_spirv.spirv_validation_builtin_variable_decorations_test

Change-Id: I7f225199954c9193ff0b5e962d4de0ca905a5a76

googlestadia/VK-GL-CTS,KhronosGroup/VK-GL-CTS,KhronosGroup/VK-GL-CTS,googlestadia/VK-GL-CTS,googlestadia/VK-GL-CTS,KhronosGroup/Vulkan-CTS,KhronosGroup/Vulkan-CTS,KhronosGroup/VK-GL-CTS,KhronosGroup/Vulkan-CTS,googlestadia/VK-GL-CTS,KhronosGroup/Vulkan-CTS,KhronosGroup/Vulkan-CTS,KhronosGroup/VK-GL-CTS,googlestadia/VK-GL-CTS,googlestadia/VK-GL-CTS,KhronosGroup/Vulkan-CTS,KhronosGroup/VK-GL-CTS,KhronosGroup/VK-GL-CTS