tests: fix http-bad-server expected errors for python 3.10 (issue6643)

The format of the error message changed with this version of Python.
This also removes obsolete Python 3 checks.

tests/test-http-bad-server.t

@@ -659,7 +659,7 b' Server sends partial bundle2 header magi'
 
   $ hg clone http://localhost:$HGPORT/ clone
   requesting all changes
-  abort: HTTP request error (incomplete response) (py3 !)
+  abort: HTTP request error (incomplete response*) (glob)
   (this may be an intermittent network failure; if the error persists, consider contacting the network or server operator)
   [255]
 
@@ -703,7 +703,7 b' Server sends incomplete bundle2 stream p'
 
   $ hg clone http://localhost:$HGPORT/ clone
   requesting all changes
-  abort: HTTP request error (incomplete response) (py3 !)
+  abort: HTTP request error (incomplete response*) (glob)
   (this may be an intermittent network failure; if the error persists, consider contacting the network or server operator)
   [255]
 
@@ -904,7 +904,7 b' Server stops after bundle2 part payload '
   adding changesets
   transaction abort!
   rollback completed
-  abort: HTTP request error (incomplete response) (py3 !)
+  abort: HTTP request error (incomplete response*) (glob)
   (this may be an intermittent network failure; if the error persists, consider contacting the network or server operator)
   [255]
 
@@ -1021,7 +1021,7 b' Server stops sending after 0 length payl'
   adding file changes
   transaction abort!
   rollback completed
-  abort: HTTP request error (incomplete response) (py3 !)
+  abort: HTTP request error (incomplete response*) (glob)
   (this may be an intermittent network failure; if the error persists, consider contacting the network or server operator)
   [255]