ToolStrip_RendersBackgroundCorrectly fails intermittently

[ToolStrip_RendersBackgroundCorrectly](https://github.com/dotnet/winforms/blob/d46ad2e8dc76248739d9ae22b28b399a6a6b299e/src/System.Windows.Forms/tests/UnitTests/System/Windows/Forms/ToolStripTests.Rendering.cs) has failed twice with `BitBltValidator did not receive expected records`.

The second BITBLT validator (`BitBltValidator`) didn't get all of the records it was expecting.

The state of the validation when it failed:

```
[ENHMETAHEADER] Bounds: {0, 0, 283, 24 (LTRB)} Device Size: {Width=1024, Height=768}Header Size: 108
[EMRCREATEBRUSHINDIRECT] Index: 1 Style: SOLID Color: [R=0, G=0, B=255]
[EMRSELECTOBJECT] Index: 1
[EMRBITBLT] Bounds: {0, 0, 283, 24 (LTRB)} Destination: {0, 0, 284, 25 (LTRB)} Rop: PATCOPYSource DC Color: [R=0, G=0, B=0] (COLOR_BACKGROUND, COLOR_MENUTEXT, COLOR_WINDOWTEXT, COLOR_CAPTIONTEXT, COLOR_BTNTEXT, COLOR_INACTIVECAPTIONTEXT, COLOR_INFOTEXT)
[EMRSELECTOBJECT] StockObject: WHITE_BRUSH
[EMRDELETEOBJECT] Index: 1
[EMRSAVEDC]
[EMRSETVIEWPORTORGEX] Point: {X=0,Y=0}
[EMRSAVEDC]
[EMREXTSELECTCLIPRGN] Mode: COPY Bounds: {0, 0, 284, 25 (LTRB)} Rects: 7
Rect index 0: {0, 0, 1, 1 (LTRB)}
Rect index 1: {281, 0, 284, 1 (LTRB)}
Rect index 2: {283, 1, 284, 3 (LTRB)}
Rect index 3: {0, 23, 1, 24 (LTRB)}
Rect index 4: {283, 23, 284, 24 (LTRB)}
Rect index 5: {0, 24, 2, 25 (LTRB)}
Rect index 6: {282, 24, 284, 25 (LTRB)}
[EMRCREATEBRUSHINDIRECT] Index: 1 Style: SOLID Color: [R=240, G=240, B=240] (COLOR_MENU, COLOR_BTNFACE, COLOR_MENUBAR)
[EMRSELECTOBJECT] Index: 1
[EMRDELETEOBJECT] Index: 1
```