d3d9: Unset the vertex shader in the compare_instructions test.

dlls/d3d9/tests/visual.c

@@ -5813,6 +5813,8 @@ void test_compare_instructions(IDirect3DDevice9 *device)
 
     hr = IDirect3DDevice9_Present(device, NULL, NULL, NULL, NULL);
     ok(hr == D3D_OK, "IDirect3DDevice9_Present failed with %08x\n", hr);
+    hr = IDirect3DDevice9_SetVertexShader(device, NULL);
+    ok(hr == D3D_OK, "IDirect3DDevice9_SetVertexShader returned %08x\n", hr);
 
     color = getPixelColor(device, 160, 360);
     ok(color == 0x00FF00FF, "Compare test: Quad 1(sge vec) returned color 0x%08x, expected 0x00FF00FF\n", color);