Winforms: Port accessibility fixes from framework runtime to core runtime

[zsd4yr]

[zsd4yr]

@bryukov @M-Lipin Would you guys mind creating a check-list here so that the community can track on-going work on these ports?

[M-Lipin]

https://github.com/dotnet/winforms/pull/400 includes the following fixes:

• Announcing the ComboBox selected value changes without expanding/collapsing drop-down list.
• Announcing DataGridView cell navigation and DataGridView editing control input's state and expanding/collapsing actions.
• Updated accessible hierarchy tree of PropertyGrid control: all editing controls are the children of corresponding property items and all items are the children of corresponding categories if PropertyGrid is in Category view.

[M-Lipin]

180 includes the following fixes:

• Keyboard tooltips fixes - user can see the control tooltip when navigating using keyboard.
• Showing keyboard tooltip for the menu items even if there is no ToolTip property for the parent control.
• Setting the ToolTip for the control (via SetToolTip) does not lead to throwing NullReferenceException.
• Navigating the strip controls (ToolStrip, MenuStrip) with accessibility client app or Inspect does not lead to throwing NonComVisibleBaseClass exception.

[M-Lipin]

Need to port the fixes related to accessibility changes in the Chart controls.

[M-Lipin]

Ported the changes related to Chart control accessibility: please see the issue 7 in DataVisualization repo.

[merriemcgaw]

@M-Lipin are there any other Accessibility fixes that need porting? If not, please feel free to close this issue and thanks for all the ports!!

[merriemcgaw]

@M-Lipin Can I close this issue?

[zsd4yr]

dotnet/winforms-datavisualization#6