Fix command test (#11812)

packages/flutter_tools/lib/src/resident_runner.dart

@@ -621,7 +621,7 @@ abstract class ResidentRunner {
         await _debugDumpSemanticsTreeInTraversalOrder();
         return true;
       }
-    } else if (character == 'P') {
+    } else if (character == 'U') {
       if (supportsServiceProtocol) {
         await _debugDumpSemanticsTreeInInverseHitTestOrder();
         return true;
@@ -759,12 +759,12 @@ abstract class ResidentRunner {
       printStatus('You can dump the widget hierarchy of the app (debugDumpApp) by pressing "w".');
       printStatus('To dump the rendering tree of the app (debugDumpRenderTree), press "t".');
       if (isRunningDebug) {
-        printStatus('For layers (debugDumpLayerTree), use "L"; accessibility (debugDumpSemantics), "S" (traversal order) or "P" (inverse hit test order).');
+        printStatus('For layers (debugDumpLayerTree), use "L"; accessibility (debugDumpSemantics), "S" (traversal order) or "U" (inverse hit test order).');
         printStatus('To toggle the widget inspector (WidgetsApp.showWidgetInspectorOverride), press "i".');
         printStatus('To toggle the display of construction lines (debugPaintSizeEnabled), press "p".');
         printStatus('To simulate different operating systems, (defaultTargetPlatform), press "o".');
       } else {
-        printStatus('To dump the accessibility tree (debugDumpSemantics), press "S" (for traversal order) or "P" (for inverse hit test order).');
+        printStatus('To dump the accessibility tree (debugDumpSemantics), press "S" (for traversal order) or "U" (for inverse hit test order).');
       }
       printStatus('To display the performance overlay (WidgetsApp.showPerformanceOverlay), press "P".');
     }