Convert wrap_here to use integer parameter

I think it only really makes sense to call wrap_here with an argument
consisting solely of spaces.  Given this, it seemed better to me that
the argument be an int, rather than a string.  This patch is the
result.  Much of it was written by a script.

gdb/cli/cli-cmds.c

@@ -841,7 +841,7 @@ echo_command (const char *text, int from_tty)
   reset_terminal_style (gdb_stdout);
 
   /* Force this output to appear now.  */
-  wrap_here ("");
+  wrap_here (0);
   gdb_flush (gdb_stdout);
 }