Revert #5423 (#5468)

I'm going to revert #5423 because it was regress -
https://github.com/xonsh/xonsh/issues/5466 - and we need to fix parser
instead of resolver.

## For community
⬇️ **Please click the 👍 reaction instead of leaving a `+1` or 👍
comment**

---------

Co-authored-by: a <1@1.1>

news/fix_redir.rst

@@ -1,23 +0,0 @@
-**Added:**
-
-* <news item>
-
-**Changed:**
-
-* <news item>
-
-**Deprecated:**
-
-* <news item>
-
-**Removed:**
-
-* <news item>
-
-**Fixed:**
-
-* Fixed redirect with python substitution e.g. ``echo 1 > @('/tmp/file')`` is working now.
-
-**Security:**
-
-* <news item>

tests/procs/test_specs.py

@@ -353,14 +353,6 @@ def test_on_command_not_found_doesnt_fire_in_non_interactive_mode(xession):
     assert not fired
 
 
-def test_redirect_to_substitution(xession):
-    s = SubprocSpec.build(
-        # `echo hello > @('file')`
-        ["echo", "hello", (">", ["file"])]
-    )
-    assert s.stdout.name == "file"
-
-
 def test_partial_args_from_classmethod(xession):
     class Class:
         @classmethod

tests/test_pipelines.py

@@ -74,6 +74,7 @@ def patched_events(monkeypatch, xonsh_events, xonsh_session):
         ("!(echo hi | grep x)", "", "", ""),
     ),
 )
+@pytest.mark.flaky(reruns=3, reruns_delay=2)
 def test_command_pipeline_capture(cmdline, stdout, stderr, raw_stdout, xonsh_execer):
     pipeline: CommandPipeline = xonsh_execer.eval(cmdline)
     assert pipeline.out == stdout

xonsh/procs/specs.py

@@ -223,9 +223,6 @@ def _parse_redirects(r, loc=None):
 
 def _redirect_streams(r, loc=None):
     """Returns stdin, stdout, stderr tuple of redirections."""
-    if isinstance(loc, list):
-        raise Exception(f"Unsupported redirect: {r!r} {loc!r}")
-
     stdin = stdout = stderr = None
     no_ampersand = r.replace("&", "")
     # special case of redirecting stderr to stdout
@@ -674,21 +671,7 @@ class SubprocSpec:
         """Weave a list of arguments into a command."""
         resolved_cmd = []
         for c in self.cmd:
-            if (
-                isinstance(c, tuple)
-                and len(c) == 2
-                and isinstance(c[1], list)
-                and len(c[1]) == 1
-            ):
-                # Redirect case e.g. `> file`
-                resolved_cmd.append(
-                    (
-                        c[0],
-                        c[1][0],
-                    )
-                )
-            else:
-                resolved_cmd += c if isinstance(c, list) else [c]
+            resolved_cmd += c if isinstance(c, list) else [c]
         self.cmd = resolved_cmd
 
     def resolve_redirects(self):