use quantum of 1 in benchmarks

tests/runner.py

@@ -2390,7 +2390,7 @@ else:
 
   global COMPILER_TEST_OPTS; COMPILER_TEST_OPTS = []
 
-  QUANTUM_SIZE = 4
+  QUANTUM_SIZE = 1
   RELOOP = OPTIMIZE = 1
   USE_TYPED_ARRAYS = 0
   ASSERTIONS = SAFE_HEAP = CHECK_OVERFLOWS = CORRECT_OVERFLOWS = CHECK_SIGNS = 0