Windows: Remove zero terminator from stack trace

Important lesson to be learned here, leaving comments
is great and in the moment, they usually make sense.

Many months later they may not quite make as much sense
any more and time will have to be spend to figure out
what was meant, all of this would have been averted with a
better comment.

The zero terminator in this case, I can find no evidence
of it being used or relied on at any point. It does however
break GTests's `EXPECT_EXIT` macro that stops looking in
the output as soon as it sees the zts and doesn't end up
looking at the actual assert text being thrown. Which in
turn makes the`fcurve_active_keyframe`test fail when run
in debug mode on windows.

source/blender/blenlib/intern/system_win32.c

@@ -386,7 +386,6 @@ void BLI_system_backtrace(FILE *fp)
     bli_windows_system_backtrace_threads(fp);
   }
   bli_windows_system_backtrace_modules(fp);
-  fputc(0, fp); /* Give our selves a nice zero terminator for later on */
 }
 
 void BLI_windows_handle_exception(EXCEPTION_POINTERS *exception)