Disable stipple in GLES rasterisation tests
Initialise stipple related fields in the LineSceneSpec so that stipple
is correctly disabled.
Components: OpenGL
VK-GL-CTS Issue: 2006
Affects: dEQP-GLES2.functional.rasterization.primitives.line*
dEQP-GLES2.functional.rasterization.interpolation.*.line*
dEQP-GLES3.functional.rasterization.primitives.line*
dEQP-GLES3.functional.rasterization.interpolation.*.line*
dEQP-GLES3.functional.rasterization.fbo.*.primitives.lines*
dEQP-GLES3.functional.rasterization.fbo.*.interpolation.lines*
Change-Id: I1df4b4cb9cac892f27f6e1d81a06061c6d974e22