tests: fix style issue of importing hgweb in embedded code fragments

Some test scripts are excluded in test-check-module-imports.t, because
import-checker.py reports that hgweb and/or hgwebdir of
mercurial.hgweb are not imported in recommended style.

To fix this issues, this patch make python code fragments embedded in
these files import hgweb from mercurial package at first, and refer
hgweb and hgwebdir via imported hgweb.

tests/test-hgweb-no-path-info.t

@@ -18,11 +18,8 b' should be used from d74fc8dec2b4 onward '
   > from __future__ import absolute_import
   > import os
   > import sys
-  > from mercurial.hgweb import (
+  > from mercurial import (
   >     hgweb,
-  >     hgwebdir,
-  > )
-  > from mercurial import (
   >     util,
   > )
   > stringio = util.stringio
@@ -72,11 +69,11 b' should be used from d74fc8dec2b4 onward '
   > 
   > output = stringio()
   > env['QUERY_STRING'] = 'style=atom'
-  > process(hgweb(b'.', name=b'repo'))
+  > process(hgweb.hgweb(b'.', name=b'repo'))
   > 
   > output = stringio()
   > env['QUERY_STRING'] = 'style=raw'
-  > process(hgwebdir({b'repo': b'.'}))
+  > process(hgweb.hgwebdir({b'repo': b'.'}))
   > EOF
   $ "$PYTHON" request.py
   ---- STATUS

tests/test-hgweb-no-request-uri.t

@@ -18,12 +18,9 b' should be used from d74fc8dec2b4 onward '
   > from __future__ import absolute_import
   > import os
   > import sys
-  > from mercurial.hgweb import (
-  >     hgweb,
-  >     hgwebdir,
-  > )
   > from mercurial import (
   >     encoding,
+  >     hgweb,
   >     util,
   > )
   > stringio = util.stringio
@@ -65,22 +62,22 b' should be used from d74fc8dec2b4 onward '
   > output = stringio()
   > env['PATH_INFO'] = '/'
   > env['QUERY_STRING'] = 'style=atom'
-  > process(hgweb(b'.', name = b'repo'))
+  > process(hgweb.hgweb(b'.', name = b'repo'))
   > 
   > output = stringio()
   > env['PATH_INFO'] = '/file/tip/'
   > env['QUERY_STRING'] = 'style=raw'
-  > process(hgweb(b'.', name = b'repo'))
+  > process(hgweb.hgweb(b'.', name = b'repo'))
   > 
   > output = stringio()
   > env['PATH_INFO'] = '/'
   > env['QUERY_STRING'] = 'style=raw'
-  > process(hgwebdir({b'repo': b'.'}))
+  > process(hgweb.hgwebdir({b'repo': b'.'}))
   > 
   > output = stringio()
   > env['PATH_INFO'] = '/repo/file/tip/'
   > env['QUERY_STRING'] = 'style=raw'
-  > process(hgwebdir({b'repo': b'.'}))
+  > process(hgweb.hgwebdir({b'repo': b'.'}))
   > EOF
   $ "$PYTHON" request.py
   ---- STATUS

tests/test-hgweb-non-interactive.t

@@ -19,9 +19,7 b' by the WSGI standard and strictly implem'
   >     util,
   > )
   > ui = uimod.ui
-  > from mercurial.hgweb.hgweb_mod import (
-  >     hgweb,
-  > )
+  > from mercurial.hgweb import hgweb_mod
   > stringio = util.stringio
   > 
   > class FileLike(object):
@@ -67,7 +65,7 b' by the WSGI standard and strictly implem'
   >     'SERVER_PROTOCOL': 'HTTP/1.0'
   > }
   > 
-  > i = hgweb(b'.')
+  > i = hgweb_mod.hgweb(b'.')
   > for c in i(env, startrsp):
   >     pass
   > sys.stdout.flush()