Normalize end2end data directory path

Given the following scenario:
```
When I open file://(testdata)/some/file.html
Then file://(testdata)/some/file.html should be loaded
```
If the end2end data directory is not normalized, the scenario fails because we try to
compare

```
file:///home/palbrecht/dev/qutebrowser/tests/helpers/../end2end/data/hints/link_inject.html?port=50…
```

to

```
file:///home/palbrecht/dev/qutebrowser/tests/end2end/data/hints/link_inject.html?port=50…
```

Normalizing the path resolves the `..` and fixes the issue.

tests/end2end/features/conftest.py

@@ -33,8 +33,7 @@ def _get_echo_exe_path():
         Path to the "echo"-utility.
     """
     if utils.is_windows:
-        return os.path.join(testutils.abs_datapath(), 'userscripts',
-                            'echo.bat')
+        return str(testutils.abs_datapath() / 'userscripts' / 'echo.bat')
     else:
         return shutil.which("echo")
 
@@ -199,7 +198,7 @@ def open_path(quteproc, server, path):
     - With "... as a URL", it's opened according to new_instance_open_target.
     """
     path = path.replace('(port)', str(server.port))
-    path = path.replace('(testdata)', testutils.abs_datapath())
+    path = path.replace('(testdata)', os.fspath(testutils.abs_datapath()))
 
     new_tab = False
     new_bg_tab = False
@@ -271,7 +270,7 @@ def run_command(quteproc, server, tmpdir, command):
         invalid = False
 
     command = command.replace('(port)', str(server.port))
-    command = command.replace('(testdata)', testutils.abs_datapath())
+    command = command.replace('(testdata)', str(testutils.abs_datapath()))
     command = command.replace('(tmpdir)', str(tmpdir))
     command = command.replace('(dirsep)', os.sep)
     command = command.replace('(echo-exe)', _get_echo_exe_path())
@@ -365,7 +364,7 @@ def hint(quteproc, args):
 
 @bdd.when(bdd.parsers.parse('I hint with args "{args}" and follow {letter}'))
 def hint_and_follow(quteproc, args, letter):
-    args = args.replace('(testdata)', testutils.abs_datapath())
+    args = args.replace('(testdata)', str(testutils.abs_datapath()))
     args = args.replace('(python-executable)', sys.executable)
     quteproc.send_cmd(':hint {}'.format(args))
     quteproc.wait_for(message='hints: *')

tests/helpers/testutils.py

@@ -192,8 +192,8 @@ def pattern_match(*, pattern, value):
 
 def abs_datapath():
     """Get the absolute path to the end2end data directory."""
-    file_abs = os.path.abspath(os.path.dirname(__file__))
-    return os.path.join(file_abs, '..', 'end2end', 'data')
+    path = pathlib.Path(__file__).parent / '..' / 'end2end' / 'data'
+    return path.resolve()
 
 
 @contextlib.contextmanager