[Utils] Fix gdb pretty printers to work with Python 3.

Reiterate D23202 for container printers added after the change landed.

Differential Revision: https://reviews.llvm.org/D46578

llvm-svn: 336580

Author: pfaffe

llvm/utils/gdb-scripts/prettyprinters.py

@@ -102,6 +102,8 @@ def next(self):
   def __init__(self, val):
     self.val = val
 
+    __next__ = next
+
   def children(self):
     data = self.val['Data']
     return self._iterator(data, data + self.val['Length'])
@@ -198,6 +200,8 @@ def next(self):
         self.first = False
       return 'x', v
 
+    __next__ = next
+
   def __init__(self, val):
     self.val = val