LibJS: Add Value(GCPtr<T>) and Value(NonnullGCPtr<T>) constructors

Let's avoid reaching for ptr() as much as possible.

Userland/Libraries/LibJS/Runtime/Value.h

@@ -18,6 +18,7 @@
 #include <AK/String.h>
 #include <AK/Types.h>
 #include <LibJS/Forward.h>
+#include <LibJS/Heap/GCPtr.h>
 #include <LibJS/Runtime/BigInt.h>
 #include <LibJS/Runtime/Utf16String.h>
 #include <math.h>
@@ -275,6 +276,18 @@ public:
     {
     }
 
+    template<typename T>
+    Value(GCPtr<T> ptr)
+        : Value(ptr.ptr())
+    {
+    }
+
+    template<typename T>
+    Value(NonnullGCPtr<T> ptr)
+        : Value(ptr.ptr())
+    {
+    }
+
     double as_double() const
     {
         VERIFY(is_number());