formatter: make 'originalnode' a thing in log-like templates

mapping['node'] doesn't work since {node} is computed dynamically in non-web
templates.

mercurial/formatter.py

@@ -514,8 +514,10 b' class templateresources(templater.resour'
         mapping = {}
         if self._hasctx(newmapping):
             mapping['revcache'] = {}  # per-ctx cache
-        if 'node' in origmapping and 'node' in newmapping:
-            mapping['originalnode'] = origmapping['node']
+        if (('node' in origmapping or self._hasctx(origmapping))
+            and ('node' in newmapping or self._hasctx(newmapping))):
+            orignode = templateutil.runsymbol(context, origmapping, 'node')
+            mapping['originalnode'] = orignode
         return mapping
 
     def _getsome(self, context, mapping, key):

tests/test-command-template.t

@@ -4199,6 +4199,13 b' Invalid arguments passed to revset()'
   hg: parse error: invalid argument for revspec
   [255]
 
+Test 'originalnode'
+
+  $ hg log -r 1 -T '{revset("null") % "{node|short} {originalnode|short}"}\n'
+  000000000000 bcc7ff960b8e
+  $ hg log -r 0 -T '{manifest % "{node} {originalnode}"}\n'
+  a0c8bcbbb45c63b90b70ad007bf38961f64f2af0 f7769ec2ab975ad19684098ad1ffd9b81ecc71a1
+
 Test files function
 
   $ hg log -T "{rev}\n{join(files('*'), '\n')}\n"