Unstable unit test: System.Windows.Forms.Tests.TreeNode_TreeNodeIKeyboardToolTipTests.TreeNodeIKeyboardToolTip_InvokeIsHoveredWithMouse_ReturnsExpected

Related #11227

### Test

System.Windows.Forms.Tests.TreeNode_TreeNodeIKeyboardToolTipTests.TreeNodeIKeyboardToolTip_InvokeIsHoveredWithMouse_ReturnsExpected(insideTreeView: True, isHovered: True, expected: True)

### Issue description

The case failed in [dotnet-winforms CI](https://dev.azure.com/dnceng-public/public/_build?definitionId=76&_a=summary), the failed scenario:

- System.Windows.Forms.Tests.TreeNode_TreeNodeIKeyboardToolTipTests.TreeNodeIKeyboardToolTip_InvokeIsHoveredWithMouse_ReturnsExpected(insideTreeView: True, isHovered: True, expected: True)

**Error Message:**

- **In X64 unit:**
- Assert.Equal() Failure: Values differ
Expected: True
Actual: False

**Stack trace:**
```
at System.Windows.Forms.Tests.TreeNode_TreeNodeIKeyboardToolTipTests.TreeNodeIKeyboardToolTip_InvokeIsHoveredWithMouse_ReturnsExpected(Boolean insideTreeView, Boolean isHovered, Boolean expected) in D:\a\_work\1\s\src\System.Windows.Forms\tests\UnitTests\System\Windows\Forms\TreeNode.IKeyboardToolTipTests.cs:line 381
at System.RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor)
at System.Reflection.MethodBaseInvoker.InvokeDirectByRefWithFewArgs(Object obj, Span`1 copyOfArgs, BindingFlags invokeAttr)
```