Revert "mesa: do not trigger _NEW_TEXTURE_STATE in glActiveTexture()"

Revert "mesa: do not trigger _NEW_TEXTURE_STATE in glActiveTexture()"

This reverts commit f314a532fdc7af8381586144d2631d9968331f05.

This appears to introduce some blinking textures in UT2004. Not
sure exactly what's the root cause because we don't have much
information about the issue.

Anyway, this was just a micro optimization that actually breaks,
at least, one app almost one year later.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105436
Cc: <mesa-stable@lists.freedesktop.org>
Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>