Remove setting of ambient to 1.0

These tests have lines with an ambient color of 1 1 1 and an ambient
intensity of 1.0.  They are colored by scalar value with a color mode
of diffuse. The old renderer ignored the ambient lighting property
when color mode diffuse was set ***ONLY*** when given lines without normals.
In all other cases it has the scalars set the diffuse and the material
properties still handle ambient and specular. This is an error in the
old renderer that the new renderer is exposing. Modified the test to leave
ambient at 0.0 so that both old and new renderer produce the desired
result.

Change-Id: Ibe041347eec76dc1be57c12e67109275731f4f96
Merge topic 'fix_bad_test' into master

a1dad768 Remove setting of ambient to 1.0