allocate immediately required fields (#1)

Reviewed-on: BigfootDev/flatbuffers-bigfoot#1
Co-authored-by: Romain BOULLARD <romain.boullard@protonmail.com>

tests/test.cpp

@@ -68,6 +68,7 @@
 #include "util_test.h"
 #include "cpp_vector_type_test.h"
 #include "bigfoot_ref_test_impl.h"
+#include "required_table_default_test.h"
 #include "vector_table_naked_ptr_test.h"
 
 void FlatBufferBuilderTest();
@@ -1817,6 +1818,7 @@ int FlatBufferTests(const std::string& tests_data_path) {
   FixedLengthArrayTest();
   NativeTypeTest();
   flatbuffers::tests::BigfootRefTest();
+  flatbuffers::tests::RequiredTableDefaultTest();
   OptionalScalarsTest();
   ParseFlexbuffersFromJsonWithNullTest();
   FlatbuffersSpanTest();