gdb: fix segfault in overload resolution debug output

gdb: fix segfault in overload resolution debug output

A segfault occurs if overload resolution debug mode is turned on via
the 'set debug overload' command.  E.g.:

~~~
$ gdb ./a.out
...
(gdb) start
...
(gdb) set debug overload 1
(gdb) print foo(5)
-- Arg is int [8], parm is double [9]
Overloaded function instance (null) # of parms 1
Segmentation fault
$
~~~

The problem is, GDB tries to print the badness vector after it has
been std::move'd.  Fix the problem by printing the vector before it is
moved.

gdb/ChangeLog:
2019-11-29  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	* valops.c (find_oload_champ): Print part of debug messages
	before the badness vector is std::move'd.

Change-Id: Ia623f9637e82ec332bfeac23eb6b0f2ffdcdde27