Enable two-sided stencil in Vulkan.

Two-sided stencil is always available in Vulkan.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1949573002

Review-Url: https://codereview.chromium.org/1949573002
diff --git a/src/gpu/vk/GrVkCaps.cpp b/src/gpu/vk/GrVkCaps.cpp
index 89b618c..746499f 100644
--- a/src/gpu/vk/GrVkCaps.cpp
+++ b/src/gpu/vk/GrVkCaps.cpp
@@ -22,7 +22,7 @@
     **************************************************************************/
     fMipMapSupport = true;   // always available in Vulkan
     fNPOTTextureTileSupport = false; //TODO: figure this out
-    fTwoSidedStencilSupport = false; //TODO: figure this out
+    fTwoSidedStencilSupport = true;  // always available in Vulkan
     fStencilWrapOpsSupport = false; //TODO: figure this out
     fDiscardRenderTargetSupport = false; //TODO: figure this out
     fReuseScratchTextures = true; //TODO: figure this out