Make sure that a PopupMenuButton doesn't crash in 0x0 environment (flutter#177493)

This is my attempt to handle
flutter#6537 for the PopupMenuButton
widget.

---------

Co-authored-by: Tong Mu <dkwingsmt@users.noreply.github.com>

Author: ahmedsameha1

packages/flutter/test/material/popup_menu_test.dart

@@ -4851,6 +4851,29 @@ void main() {
     checkPopupMenu(popupMenuTheme2);
   });
 
+  testWidgets('PopupMenuButton does not crash at zero area', (WidgetTester tester) async {
+    // This test case only verifies the layout of the button itself, not the
+    // overlay, because there doesn't seem to be a way to open the menu at zero
+    // area. Though, this should be sufficient since the overlay has been verified
+    // by similar tests for MenuAnchor and PopupMenuItem.
+    tester.view.physicalSize = Size.zero;
+    addTearDown(tester.view.reset);
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Center(
+          child: SizedBox.shrink(
+            child: PopupMenuButton<String>(
+              itemBuilder: (BuildContext context) => <PopupMenuItem<String>>[
+                const PopupMenuItem<String>(value: 'X', child: Text('X')),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+    expect(tester.getSize(find.byType(PopupMenuButton<String>)), Size.zero);
+  });
+
   testWidgets('PopupMenuDivider does not crash at zero area', (WidgetTester tester) async {
     await tester.pumpWidget(
       const MaterialApp(