fuzz: pass coins_view_cache to TestCoinsView in coins_view

Refactor TestCoinsView() to accept the cache as a parameter instead of
creating it internally. This prepares for adding a CoinsViewOverlay
fuzz target that needs to pass in a different cache type.

This is a non-functional change.

Co-authored-by: l0rinc <pap.lorinc@gmail.com>

src/test/fuzz/coins_view.cpp

@@ -42,11 +42,10 @@ void initialize_coins_view()
     static const auto testing_setup = MakeNoLogFileContext<>();
 }
 
-void TestCoinsView(FuzzedDataProvider& fuzzed_data_provider, CCoinsView& backend_coins_view, bool is_db)
+void TestCoinsView(FuzzedDataProvider& fuzzed_data_provider, CCoinsViewCache& coins_view_cache, CCoinsView& backend_coins_view, bool is_db)
 {
     bool good_data{true};
 
-    CCoinsViewCache coins_view_cache{&backend_coins_view, /*deterministic=*/true};
     if (is_db) coins_view_cache.SetBestBlock(uint256::ONE);
     COutPoint random_out_point;
     Coin random_coin;
@@ -312,7 +311,8 @@ FUZZ_TARGET(coins_view, .init = initialize_coins_view)
 {
     FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};
     CCoinsView backend_coins_view;
-    TestCoinsView(fuzzed_data_provider, backend_coins_view, /*is_db=*/false);
+    CCoinsViewCache coins_view_cache{&backend_coins_view, /*deterministic=*/true};
+    TestCoinsView(fuzzed_data_provider, coins_view_cache, backend_coins_view, /*is_db=*/false);
 }
 
 FUZZ_TARGET(coins_view_db, .init = initialize_coins_view)
@@ -323,6 +323,7 @@ FUZZ_TARGET(coins_view_db, .init = initialize_coins_view)
         .cache_bytes = 1_MiB,
         .memory_only = true,
     };
-    CCoinsViewDB coins_db{std::move(db_params), CoinsViewOptions{}};
+    CCoinsViewDB backend_coins_view{std::move(db_params), CoinsViewOptions{}};
-    TestCoinsView(fuzzed_data_provider, coins_db, /*is_db=*/true);
+    CCoinsViewCache coins_view_cache{&backend_coins_view, /*deterministic=*/true};
+    TestCoinsView(fuzzed_data_provider, coins_view_cache, backend_coins_view, /*is_db=*/true);
 }