Fix logic bug in JIT_CHECK_ONCE macro where check ran every time

Summary:
The checked flag was only set to true in the else branch (reached when
checked is already true), so it never actually became true and the
"once" semantics were completely broken.

Reviewed By: yoney

Differential Revision: D94927042

fbshipit-source-id: b4a81c562542ebc29604f5a532032279853b1fc9

Author: alexmalyshev

cinderx/Common/log.h

@@ -70,9 +70,8 @@ std::string repr(BorrowedRef<> obj);
   {                                 \
     static bool checked = false;    \
     if (!checked) {                 \
-      JIT_CHECK(COND, __VA_ARGS__); \
-    } else {                        \
       checked = true;               \
+      JIT_CHECK(COND, __VA_ARGS__); \
     }                               \
   }