Revert "Update Object.GetObject() to use JniRuntime.JniValueManager"

This reverts commit f3c122e.

This doens't build, because d3cde47 turns all warnings into errors,
and this commit introduces a warning.

PR #9728 is the proper fix.

src/Mono.Android/Java.Lang/Object.cs

@@ -156,9 +156,13 @@ protected void SetHandle (IntPtr value, JniHandleOwnership transfer)
 			if (handle == IntPtr.Zero)
 				return null;
 
-			var p   = JNIEnvInit.ValueManager!.GetPeer (new JniObjectReference (handle), type);
-			JNIEnv.DeleteRef (handle, transfer);
-			return p;
+			var r = PeekObject (handle, type);
+			if (r != null) {
+				JNIEnv.DeleteRef (handle, transfer);
+				return r;
+			}
+
+			return Java.Interop.TypeManager.CreateInstance (handle, transfer, type);
 		}
 
 		[EditorBrowsable (EditorBrowsableState.Never)]