glsl: add packed varyings to program resource list

glsl: add packed varyings to program resource list

This makes sure that user is still able to query properties about
variables that have gotten packed by lower_packed_varyings pass.

Fixes following OpenGL ES 3.1 test:
   ES31-CTS.program_interface_query.separate-programs-vertex

v2: fix 'name included in packed list' check (Ilia Mirkin)
v3: iterate over instances of name using strtok_r (Ilia Mirkin)

Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Marta Lofstedt <marta.lofstedt@intel.com>