Fixed #25848 -- Set template origin on each node.

Prior to 55f12f8709, the template origin was available on each node via
`self.token.source[0]`. This behavior was removed when debug handling was
simplified, but 3rd-party debugging tools still depend on its presence.
This updates the Parser to set origin on individual nodes. This enables the
source template to be determined even when template extending or including is
used.

django/template/base.py

@@ -225,6 +225,7 @@ class Template(object):
         tokens = lexer.tokenize()
         parser = Parser(
             tokens, self.engine.template_libraries, self.engine.template_builtins,
+            self.origin,
         )
 
         try:
@@ -445,7 +446,7 @@ class DebugLexer(Lexer):
 
 
 class Parser(object):
-    def __init__(self, tokens, libraries=None, builtins=None):
+    def __init__(self, tokens, libraries=None, builtins=None, origin=None):
         self.tokens = tokens
         self.tags = {}
         self.filters = {}
@@ -459,6 +460,7 @@ class Parser(object):
         self.libraries = libraries
         for builtin in builtins:
             self.add_library(builtin)
+        self.origin = origin
 
     def parse(self, parse_until=None):
         """
@@ -535,8 +537,10 @@ class Parser(object):
             )
         if isinstance(nodelist, NodeList) and not isinstance(node, TextNode):
             nodelist.contains_nontext = True
-        # Set token here since we can't modify the node __init__ method
+        # Set origin and token here since we can't modify the node __init__()
+        # method.
         node.token = token
+        node.origin = self.origin
         nodelist.append(node)
 
     def error(self, token, e):