tests: make hg frame optional

When `hg` is a Rust binary, the `hg` frame doesn't exist because an
`hg` Python script doesn't exist.

This commit updates expected test output to make the `hg` frame
optional.

There /might/ be a way to do this more accurately with the
"(feature !)" syntax in .t files. However, I poked at it for a
few minutes and couldn't get it to work. Worst case with using
(?) is we drop the frame from output for Python `hg`. The `hg`
frame isn't terribly important. So the worst case doesn't feel that
bad. If someone wants to enlighten me on how to use "(feature !)"
for optional output based on hghave features, I'd be more than
willing to update this.

Differential Revision: https://phab.mercurial-scm.org/D1858

tests/test-devel-warnings.t

@@ -99,7 +99,7 b''
 #if no-chg
   $ hg buggylocking --traceback
   devel-warn: "wlock" acquired after "lock" at:
-   */hg:* in <module> (glob)
+   */hg:* in <module> (glob) (?)
    */mercurial/dispatch.py:* in run (glob)
    */mercurial/dispatch.py:* in dispatch (glob)
    */mercurial/dispatch.py:* in _runcatch (glob)
@@ -115,7 +115,7 b''
 #else
   $ hg buggylocking --traceback
   devel-warn: "wlock" acquired after "lock" at:
-   */hg:* in <module> (glob)
+   */hg:* in <module> (glob) (?)
    */mercurial/dispatch.py:* in run (glob)
    */mercurial/dispatch.py:* in dispatch (glob)
    */mercurial/dispatch.py:* in _runcatch (glob)
@@ -177,7 +177,7 b' Stripping from a transaction'
   $ hg oldanddeprecated --traceback
   devel-warn: foorbar is deprecated, go shopping
   (compatibility will be dropped after Mercurial-42.1337, update your code.) at:
-   */hg:* in <module> (glob)
+   */hg:* in <module> (glob) (?)
    */mercurial/dispatch.py:* in run (glob)
    */mercurial/dispatch.py:* in dispatch (glob)
    */mercurial/dispatch.py:* in _runcatch (glob)
@@ -238,7 +238,7 b' Stripping from a transaction'
   1970/01/01 00:00:00 bob @cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b (5000)> oldanddeprecated --traceback
   1970/01/01 00:00:00 bob @cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b (5000)> devel-warn: foorbar is deprecated, go shopping
   (compatibility will be dropped after Mercurial-42.1337, update your code.) at:
-   */hg:* in <module> (glob)
+   */hg:* in <module> (glob) (?)
    */mercurial/dispatch.py:* in run (glob)
    */mercurial/dispatch.py:* in dispatch (glob)
    */mercurial/dispatch.py:* in _runcatch (glob)