layers: Add extension Validation so loader will add layers with Validation

Also fix extension supported list in DrawState and ObjectTracker to include
their local extensions in GetGlobalExtensionInfo()
diff --git a/layers/param_checker.cpp b/layers/param_checker.cpp
index c3cc839..9455074 100644
--- a/layers/param_checker.cpp
+++ b/layers/param_checker.cpp
@@ -262,10 +262,11 @@
     const char * const name;
 };
 
-#define PARAM_CHECKER_LAYER_EXT_ARRAY_SIZE 1
+#define PARAM_CHECKER_LAYER_EXT_ARRAY_SIZE 2
 static const struct extProps pcExts[PARAM_CHECKER_LAYER_EXT_ARRAY_SIZE] = {
     // TODO what is the version?
     0x10, "ParamChecker",
+    0x10, "Validation",
 };
 
 VK_LAYER_EXPORT VkResult VKAPI vkGetGlobalExtensionInfo(