when basicGLLineRasterization or supportsTransformFeedbackExtension is enabled.
updated with MaxVaryingWithFeedbackAndGLline
adding test to validate pixel value (disabled for macos)

Bug: angleproject:4273
Change-Id: Ie3d3516fd3806c0d622fb402ba8223d302206f73
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2071237
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>