FIX Quicktests

Vectorisation test case was always set to avx which is problematic on machines not having avx.

pystencils_tests/test_vectorization.py

@@ -9,7 +9,7 @@ from pystencils.transformations import replace_inner_stride_with_one
 
 supported_instruction_sets = get_supported_instruction_sets()
 if supported_instruction_sets:
-    instruction_set = "avx" if "avx" in supported_instruction_sets else "sse"
+    instruction_set = supported_instruction_sets[-1]
 else:
     instruction_set = None