i965/nir: Report NIR instruction counts (in SSA form) via KHR_debug.

i965/nir: Report NIR instruction counts (in SSA form) via KHR_debug.

This allows us to count NIR instructions via shader-db.

Use "run" as normal.  The results file will contain both NIR and
assembly.

Then, to generate a NIR report:
./report.py <(grep    NIR results/foo) <(grep    NIR results/bar)

Or, to generate an i965 report:
./report.py <(grep -v NIR results/foo) <(grep -v NIR results/bar)

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>