Fix gdb pretty printers to work with Python 3.

[philip.pfaffe]

Summary

Reiterate D23202 for container printers added after the change landed.

[philip.pfaffe]

Ping

[dblaikie]

I don't happen to have a setup to test this - but if it works for you, I'm fine with it :)

llvm/trunk/utils/gdb-scripts/prettyprinters.py

def next(self):
       self.cur = self.cur + 1
       return '[%d]' % count, cur.dereference()
 
     __next__ = next
 
   def __init__(self, val):
     self.val = val
 
+    __next__ = next
+
   def children(self):
     data = self.val['Data']
     return self._iterator(data, data + self.val['Length'])
 
   def to_string(self):
     return 'llvm::ArrayRef of length %d' % (self.val['Length'])
 
   def display_hint (self):
def next(self):
       if not self.first:
         self.cur = self.cur + 1
         self.advancePastEmptyBuckets()
         self.first = True
       else:
         self.first = False
       return 'x', v
 
+    __next__ = next
+
   def __init__(self, val):
     self.val = val
 
   def children(self):
     t = self.val.type.template_argument(3).pointer()
     begin = self.val['Buckets'].cast(t)
     end = (begin + self.val['NumBuckets']).cast(t)
     return self._iterator(self.val.type.template_argument(2), begin, end)