Debugger: Work around strange GDB behavior with overload resolution

Contrary to the documention, using the default (i.e. 'on') it seems to _require_
xplicit casting of function pointers:
 (gdb) p &Myns::QMetaType::typeName
    -> $1 = (const char *(*)(int)) 0xb7cf73b0 <Myns::QMetaType::typeName(int)>
 (gdb) p Myns::QMetaType::typeName(1024)
     -> 31^error,msg="Couldn't find method Myns::QMetaType::typeName"
But we can work around on the dumper side. So let's use the default from now on.

Change-Id: I3e2a87df797c6abab6183b4c121b843e5035cd47
Reviewed-by: hjk <hjk121@nokiamail.com>