mesa: Flag _NEW_VARYING_VP_INPUTS when TexEnv programs are active.

mesa: Flag _NEW_VARYING_VP_INPUTS when TexEnv programs are active.

The idea here is to not flag _NEW_VARYING_VP_INPUTS when shaders (either
GLSL or ARB vp/fp) are in use.  If either TNL or TexEnv programs are
active, at least one stage is using fixed function.

On Pineview, fixes 20 Piglit, 60 oglconforms, and 7 ES 1.1 conformance
tests, as well as missing textures in Xonotic.  These were all
regressions since commit fb4a34e60eb4c1bdc7b0fdcd98d1bf3038c354e8.

NOTE: This is a candidate for the 9.0 branch.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=49127
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=54807
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>