all: cleanup tests (#25641)

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

eth/tracers/api_test.go

@@ -61,20 +61,14 @@ type testBackend struct {
 
 func newTestBackend(t *testing.T, n int, gspec *core.Genesis, generator func(i int, b *core.BlockGen)) *testBackend {
 	backend := &testBackend{
-		chainConfig: params.TestChainConfig,
+		chainConfig: gspec.Config,
 		engine:      ethash.NewFaker(),
 		chaindb:     rawdb.NewMemoryDatabase(),
 	}
 	// Generate blocks for testing
-	gspec.Config = backend.chainConfig
-	var (
-		gendb   = rawdb.NewMemoryDatabase()
-		genesis = gspec.MustCommit(gendb)
-	)
-	blocks, _ := core.GenerateChain(backend.chainConfig, genesis, backend.engine, gendb, n, generator)
+	_, blocks, _ := core.GenerateChainWithGenesis(gspec, backend.engine, n, generator)
 
 	// Import the canonical chain
-	gspec.MustCommit(backend.chaindb)
 	cacheConfig := &core.CacheConfig{
 		TrieCleanLimit:    256,
 		TrieDirtyLimit:    256,