Disable VertexFormatTest for D3D12 + tint

Bug: tint:687
Change-Id: Ib839f629ea4095c007c1a8b3f9ad490c1e9e4910
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/46373
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>

src/tests/end2end/VertexFormatTests.cpp

@@ -49,6 +49,9 @@ class VertexFormatTest : public DawnTest {
     void SetUp() override {
         DawnTest::SetUp();
 
+        // TODO(crbug.com/tint/687): error: struct member tint_first_vertex_index not found
+        DAWN_SKIP_TEST_IF(IsD3D12() && HasToggleEnabled("use_tint_generator"));
+
         renderPass = utils::CreateBasicRenderPass(device, kRTSize, kRTSize);
     }