Failing test: Updates "un-committed" when rebasing

Adds a failing test case where an update that was committed is
later skipped over during a rebase. This should never happen.

packages/react-reconciler/src/__tests__/ReactIncrementalUpdates-test.internal.js

@@ -653,4 +653,48 @@ describe('ReactIncrementalUpdates', () => {
       expect(Scheduler).toFlushAndYield(['Commit: goodbye']);
     });
   });
+
+  it('when rebasing, does not exclude updates that were already committed, regardless of priority', async () => {
+    const {useState, useLayoutEffect} = React;
+
+    let pushToLog;
+    function App() {
+      const [log, setLog] = useState('');
+      pushToLog = msg => {
+        setLog(prevLog => (prevLog += msg));
+      };
+
+      useLayoutEffect(
+        () => {
+          Scheduler.unstable_yieldValue('Committed: ' + log);
+          if (log === 'B') {
+            setLog(prevLog => (prevLog += 'C'));
+          }
+        },
+        [log],
+      );
+
+      return log;
+    }
+
+    const root = ReactNoop.createRoot();
+    await ReactNoop.act(async () => {
+      root.render(<App />);
+    });
+    expect(Scheduler).toHaveYielded(['Committed: ']);
+    expect(root).toMatchRenderedOutput('');
+
+    await ReactNoop.act(async () => {
+      pushToLog('A');
+      ReactNoop.discreteUpdates(() => {
+        pushToLog('B');
+      });
+    });
+    expect(Scheduler).toHaveYielded([
+      'Committed: B',
+      'Committed: BC',
+      'Committed: ABC',
+    ]);
+    expect(root).toMatchRenderedOutput('ABC');
+  });
 });