test: fix g++ compile errors

src/core_test/helper/block_num.h

@@ -37,7 +37,7 @@ const std::vector<block_num_t>& block_nums();
 namespace std {
 
 template <>
-struct std::hash<helper::block_num_t> {
+struct hash<helper::block_num_t> {
     size_t operator()(const helper::block_num_t val) const noexcept {
         return (val.n_1x1 << 6) ^ (val.n_1x2 << 3) ^ val.n_2x1;
     }

src/core_test/helper/hash.h

@@ -6,8 +6,10 @@
 /// They do not guarantee the security of the hash algorithm, as this scenario
 /// is only used to verify the correctness of the data.
 
+#include <string>
 #include <vector>
 #include <cstdint>
+#include <string_view>
 
 namespace helper {