Revert "Fix handling backspace on macos with text selection (#49760)" (#51577)

This reverts commit 9375377f.

Fixes #51511

packages/flutter/lib/src/rendering/editable.dart

@@ -437,17 +437,12 @@ class RenderEditable extends RenderBox with RelayoutWhenSystemFontsChangeMixin {
     LogicalKeyboardKey.arrowDown,
   };
 
-  static final Set<LogicalKeyboardKey> _deleteKeys = <LogicalKeyboardKey>{
-    LogicalKeyboardKey.delete,
-    LogicalKeyboardKey.backspace,
-  };
-
   static final Set<LogicalKeyboardKey> _shortcutKeys = <LogicalKeyboardKey>{
     LogicalKeyboardKey.keyA,
     LogicalKeyboardKey.keyC,
     LogicalKeyboardKey.keyV,
     LogicalKeyboardKey.keyX,
-    ..._deleteKeys,
+    LogicalKeyboardKey.delete,
   };
 
   static final Set<LogicalKeyboardKey> _nonModifierKeys = <LogicalKeyboardKey>{
@@ -502,7 +497,7 @@ class RenderEditable extends RenderBox with RelayoutWhenSystemFontsChangeMixin {
       // _handleShortcuts depends on being started in the same stack invocation
       // as the _handleKeyEvent method
       _handleShortcuts(key);
-    } else if (_deleteKeys.contains(key)) {
+    } else if (key == LogicalKeyboardKey.delete) {
       _handleDelete();
     }
   }

packages/flutter/test/widgets/editable_text_test.dart

@@ -3741,51 +3741,6 @@ void main() {
       reason: 'on $platform',
     );
     expect(controller.text, isEmpty, reason: 'on $platform');
-
-    /// Paste and Select All
-    await sendKeys(
-      tester,
-      <LogicalKeyboardKey>[
-        LogicalKeyboardKey.keyV,
-        LogicalKeyboardKey.keyA,
-      ],
-      shortcutModifier: true,
-      platform: platform,
-    );
-
-    expect(
-      selection,
-      equals(
-        const TextSelection(
-          baseOffset: 0,
-          extentOffset: testText.length,
-          affinity: TextAffinity.downstream,
-        ),
-      ),
-      reason: 'on $platform',
-    );
-    expect(controller.text, equals(testText), reason: 'on $platform');
-
-    // Backspace
-    await sendKeys(
-      tester,
-      <LogicalKeyboardKey>[
-        LogicalKeyboardKey.delete,
-      ],
-      platform: platform,
-    );
-    expect(
-      selection,
-      equals(
-        const TextSelection(
-          baseOffset: 0,
-          extentOffset: 72,
-          affinity: TextAffinity.downstream,
-        ),
-      ),
-      reason: 'on $platform',
-    );
-    expect(controller.text, isEmpty, reason: 'on $platform');
   }
 
   testWidgets('keyboard text selection works as expected on linux', (WidgetTester tester) async {