Vulkan fixes for TesselatingPathRenderer test

- Be sure to release all secondard command buffers on shutdown
- Allow mapping of static buffers
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2123323002

Review-Url: https://codereview.chromium.org/2123323002
diff --git a/src/gpu/vk/GrVkResourceProvider.cpp b/src/gpu/vk/GrVkResourceProvider.cpp
index 7980a2d..c7a66ca 100644
--- a/src/gpu/vk/GrVkResourceProvider.cpp
+++ b/src/gpu/vk/GrVkResourceProvider.cpp
@@ -270,6 +270,7 @@
     for (int i = 0; i < fActiveCommandBuffers.count(); ++i) {
         SkASSERT(fActiveCommandBuffers[i]->finished(fGpu));
         SkASSERT(fActiveCommandBuffers[i]->unique());
+        fActiveCommandBuffers[i]->reset(fGpu);
         fActiveCommandBuffers[i]->unref(fGpu);
     }
     fActiveCommandBuffers.reset();