Add "native" discriminant.

Author: ArnaudCharlet

fixedbugs/Makefile

@@ -9,4 +9,4 @@ save-results:
 run:
 	(cd support; ./testsuite.py -o ../output/new --old-output-dir=../output/old --jobs=12 \
   --tests-dir=../bugs --test-sections=fixed --max-consecutive-failures=30 \
-  --target=llvm --discriminants=linux,Linux,x86_64-linux,x86_64)
+  --target=llvm --discriminants=native,linux,Linux,x86_64-linux,x86_64)