test/bench: verify hash in ComputeFilter reads

Switch to the index-aware `ReadBlock()` overload in `ComputeFilter` so that filter creation will abort if the stored block header hash doesn't match the expected one.

In the `readwriteblock` benchmark, pass the expected hash to `ReadBlock()` to match the new signature without affecting benchmark performance.

src/bench/readwriteblock.cpp

@@ -42,10 +42,12 @@ static void ReadBlockBench(benchmark::Bench& bench)
 {
     const auto testing_setup{MakeNoLogFileContext<const TestingSetup>(ChainType::MAIN)};
     auto& blockman{testing_setup->m_node.chainman->m_blockman};
-    const auto pos{blockman.WriteBlock(CreateTestBlock(), 413'567)};
+    const auto& test_block{CreateTestBlock()};
-    CBlock block;
+    const auto& expected_hash{test_block.GetHash()};
+    const auto& pos{blockman.WriteBlock(test_block, 413'567)};
     bench.run([&] {
-        const auto success{blockman.ReadBlock(block, pos)};
+        CBlock block;
+        const auto success{blockman.ReadBlock(block, pos, expected_hash)};
         assert(success);
     });
 }

src/test/util/blockfilter.cpp

@@ -17,7 +17,7 @@ bool ComputeFilter(BlockFilterType filter_type, const CBlockIndex& block_index,
     LOCK(::cs_main);
 
     CBlock block;
-    if (!blockman.ReadBlock(block, block_index.GetBlockPos())) {
+    if (!blockman.ReadBlock(block, block_index)) {
         return false;
     }