[red-knot] Add control flow support for match statement (#13241)

## Summary

This PR adds support for control flow for match statement.

It also adds the necessary infrastructure required for narrowing
constraints in case blocks and implements the logic for
`PatternMatchSingleton` which is either `None` / `True` / `False`. Even
after this the inferred type doesn't get simplified completely, there's
a TODO for that in the test code.

## Test Plan

Add test cases for control flow for (a) when there's a wildcard pattern
and (b) when there isn't. There's also a test case to verify the
narrowing logic.

---------

Co-authored-by: Carl Meyer <carl@astral.sh>

crates/ruff_python_ast/src/nodes.rs

@@ -3124,6 +3124,29 @@ impl Pattern {
             _ => false,
         }
     }
+
+    /// Checks if the [`Pattern`] is a [wildcard pattern].
+    ///
+    /// The following are wildcard patterns:
+    /// ```python
+    /// match subject:
+    ///     case _ as x: ...
+    ///     case _ | _: ...
+    ///     case _: ...
+    /// ```
+    ///
+    /// [wildcard pattern]: https://docs.python.org/3/reference/compound_stmts.html#wildcard-patterns
+    pub fn is_wildcard(&self) -> bool {
+        match self {
+            Pattern::MatchAs(PatternMatchAs { pattern, .. }) => {
+                pattern.as_deref().map_or(true, Pattern::is_wildcard)
+            }
+            Pattern::MatchOr(PatternMatchOr { patterns, .. }) => {
+                patterns.iter().all(Pattern::is_wildcard)
+            }
+            _ => false,
+        }
+    }
 }
 
 /// See also [MatchValue](https://docs.python.org/3/library/ast.html#ast.MatchValue)