Fix string-conversion issue in cinderx/Shadowcode/shadowcode.c +1

Summary:
This could is triggering `-Wstring-conversion`, which presents as:
```
warning: implicit conversion turns string literal into bool: A to B
```
This is often a bug and what was intended. The most frequent cause is the code was:
```
void foo(bool) { ... }
void foo(std::string) { ... }
foo("this gets interpreted as a bool");
```

It is also possible the issue is innocuous as part of an assert:
```
assert(!"this string is true, so the assertion is false");
EXPECT_FALSE("this string is true, so the expect fails");
```
in these cases the use is to "cute", so we modify the code to make it more obvious.
```
assert(false && "the compiler recognizes and doesn't complain about this pattern");
FAIL() << "much more obvious";
```

Reviewed By: alexmalyshev

Differential Revision: D92528315

fbshipit-source-id: 3d6c932d59b0205d77dd60e17b4104a50747309d

Author: r-barnes

cinderx/Shadowcode/shadowcode.c

@@ -993,8 +993,6 @@ void _PyShadow_InitGlobal(
     return;
   }
 
-  assert("Shadowcode broken");
-
   PyObject** cache = Ci_GetGlobalCache(builtins, globals, name);
   if (cache == NULL) {
     return;