some fix

tests/27_goto.py

@@ -35,4 +35,4 @@ assert sum == 5050
 for i in range(4):
     _ = 0
 # if there is no op here, the block check will fail
-while i: --i
+while i: i-=1

tests/99_bugs.py

@@ -66,7 +66,7 @@ assert f((
 def f():
     for i in range(4):
         _ = 0
-    while i: --i
+    while i: i-=1
 f()
 
 # class A: a=b=1