Accept compiler or link error as passing result

Accept compiler or link error as passing result

Accept either a compiler or link error as a correct behavior when
attempting to alias two outputs from a shader.

Also updates the documentation in the header with the actual shader
construct being tested.

VK-GL-CTS issue: 504
Components: OpenGL

Affects:

KHR-GL44.geometry_shader.linking.location_aliasing
KHR-GL45.geometry_shader.linking.location_aliasing
KHR-GLES31.core.geometry_shader.linking.location_aliasing
KHR-GLES32.core.geometry_shader.linking.location_aliasing

Change-Id: Ib786b3e2bd4f8efc94bea082da417e20e7b8619c