test/binding: inherit PhysicalGpu from Handle

And rename PhysicalGpu to PhysicalDevice, gpu to phy.
diff --git a/tests/blit_tests.cpp b/tests/blit_tests.cpp
index 9c301ec..d93ef25 100644
--- a/tests/blit_tests.cpp
+++ b/tests/blit_tests.cpp
@@ -777,7 +777,7 @@
         mem_info.allocationSize = mem_req.size;
         mem_info.memoryTypeIndex = 0;
 
-        err = dev_.gpu().set_memory_type(mem_req.memoryTypeBits, &mem_info, 0);
+        err = dev_.phy().set_memory_type(mem_req.memoryTypeBits, &mem_info, 0);
         ASSERT_VK_SUCCESS(err);
 
         err = vkAllocMemory(dev_.obj(), &mem_info, &event_mem);
@@ -1301,7 +1301,7 @@
         VkFormatProperties props;
         VkResult err;
 
-        err = vkGetPhysicalDeviceFormatInfo(dev_.gpu().obj(), it->format, &props);
+        err = vkGetPhysicalDeviceFormatInfo(dev_.phy().handle(), it->format, &props);
         ASSERT_EQ(err, VK_SUCCESS);
 
         if (it->tiling == VK_IMAGE_TILING_LINEAR && !(props.linearTilingFeatures & VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT))
@@ -1468,7 +1468,7 @@
         VkFormatProperties props;
         VkResult err;
 
-        err = vkGetPhysicalDeviceFormatInfo(dev_.gpu().obj(), it->format, &props);
+        err = vkGetPhysicalDeviceFormatInfo(dev_.phy().handle(), it->format, &props);
         ASSERT_EQ(err, VK_SUCCESS);
 
         if (it->tiling == VK_IMAGE_TILING_LINEAR && !(props.linearTilingFeatures & VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT))