all: cleanup tests (#25641)

Follow-up to PR #25523 to cleanup all relevant tests.

eth/fetcher/block_fetcher_test.go

@@ -39,7 +39,8 @@ var (
 	testdb      = rawdb.NewMemoryDatabase()
 	testKey, _  = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
 	testAddress = crypto.PubkeyToAddress(testKey.PublicKey)
-	gspec       = core.Genesis{
+	gspec       = &core.Genesis{
+		Config:  params.TestChainConfig,
 		Alloc:   core.GenesisAlloc{testAddress: {Balance: big.NewInt(1000000000000000)}},
 		BaseFee: big.NewInt(params.InitialBaseFee),
 	}
@@ -52,7 +53,7 @@ var (
 // contains a transaction and every 5th an uncle to allow testing correct block
 // reassembly.
 func makeChain(n int, seed byte, parent *types.Block) ([]common.Hash, map[common.Hash]*types.Block) {
-	blocks, _ := core.GenerateChain(params.TestChainConfig, parent, ethash.NewFaker(), testdb, n, func(i int, block *core.BlockGen) {
+	blocks, _ := core.GenerateChain(gspec.Config, parent, ethash.NewFaker(), testdb, n, func(i int, block *core.BlockGen) {
 		block.SetCoinbase(common.Address{seed})
 
 		// If the block number is multiple of 3, send a bonus transaction to the miner