Add VK_EXT_metal_surface extension support

VK_EXT_metal_surface is a similar extension to VK_MVK_macos_surface,
which is already supported.

Bug: chromium:1015454
Change-Id: I08d8e6b097d75236f724984b8c7d20251a63581f
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/37808
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Tested-by: Jonah Ryan-Davis <jonahr@google.com>
diff --git a/src/WSI/BUILD.gn b/src/WSI/BUILD.gn
index 15c21e2..17cf87b 100644
--- a/src/WSI/BUILD.gn
+++ b/src/WSI/BUILD.gn
@@ -42,8 +42,8 @@
 
   if (is_mac) {
     sources += [
-      "MacOSSurfaceMVK.mm",
-      "MacOSSurfaceMVK.h"
+      "MetalSurface.mm",
+      "MetalSurface.h",
     ]
     libs = [
       "Cocoa.framework",