Fix undefined behaviors (#14365)

* Initialize member `floats` in ContentFeatures

* Do not assign big double to u32

* Do not assign negative floating point number to unsigned integer

src/nodedef.cpp

@@ -356,6 +356,8 @@ void ContentFeatures::reset()
 	has_on_construct = false;
 	has_on_destruct = false;
 	has_after_destruct = false;
+	floats = false;
+	
 	/*
 		Actual data