tests: Stabilize reloading in tests

The test added in fbd148f983 was flaky because
reloading didn't wait for the page load to actually finish fully, and thus the
element not being found on the page.

Fix this by providing the page path to the step, and making sure it waits for it
to be fully loaded again.

Also undos some flaky tags done in 2018:
12e5375931
c1c182d958

As this might have been the real culprit.
If not, those should be re-added.

See #8348, #5390

tests/end2end/features/backforward.feature

@@ -1,17 +1,16 @@
 Feature: Going back and forward.
     Testing the :back/:forward commands.
 
-    @skip  # Too flaky
     Scenario: Going back/forward
         Given I open data/backforward/1.txt
         When I open data/backforward/2.txt
         And I run :tab-only
         And I run :back
         And I wait until data/backforward/1.txt is loaded
-        And I reload
+        And I reload data/backforward/1.txt
         And I run :forward
         And I wait until data/backforward/2.txt is loaded
-        And I reload
+        And I reload data/backforward/2.txt
         Then the session should look like:
             """
                 windows:
@@ -81,7 +80,6 @@ Feature: Going back and forward.
                     - url: http://localhost:*/data/backforward/2.txt
             """
 
-    @flaky
     Scenario: Going back with count.
         Given I open data/backforward/1.txt
         When I open data/backforward/2.txt
@@ -89,7 +87,7 @@ Feature: Going back and forward.
         And I run :tab-only
         And I run :back with count 2
         And I wait until data/backforward/1.txt is loaded
-        And I reload
+        And I reload data/backforward/1.txt
         Then the session should look like:
             """
                 windows:

tests/end2end/features/conftest.py

@@ -278,11 +278,12 @@ def run_command(quteproc, server, tmpdir, command):
     quteproc.send_cmd(command, count=count, invalid=invalid)
 
 
-@bdd.when(bdd.parsers.parse("I reload"))
-def reload(qtbot, server, quteproc):
+@bdd.when(bdd.parsers.parse("I reload {path}"))
+def reload(qtbot, server, quteproc, path):
     """Reload and wait until a new request is received."""
     with qtbot.wait_signal(server.new_request):
         quteproc.send_cmd(':reload')
+        quteproc.wait_for_load_finished(path)
 
 
 @bdd.when(bdd.parsers.parse("I wait until {path} is loaded"))

tests/end2end/features/prompts.feature

@@ -280,7 +280,7 @@ Feature: Prompts
         And I wait for a prompt
         And I run :prompt-accept --save yes
         And I wait for "*Text pasted: *" in the log
-        And I reload
+        And I reload data/prompt/clipboard.html
         And I run :click-element id paste
         Then the javascript message "Text pasted: *" should be logged