4. test(db): add large transaction tests (#3759)

* refactor(test/block): rename large single transaction function

```sh
fastmod single_transaction_block single_transaction_block_many_inputs
```

* rustfmt

* test(block): add a test block with many transparent outputs

* doc(db): explain why we can't just get the UTXOs right before they are deleted

* refactor(db): split out a block data write method

* refactor(block): add a height argument to new_outputs

* test(db): add block and transaction round-trip tests

Including large blocks and transactions.

* test(db): fix large block serialization instability in the tests

* doc(block): add TODOs for generating correct blocks

* Make transparent output functions which take a height test-only

* make sure generated blocks are actually over/under-sized

* replace println!() with an error!() log

zebra-chain/benches/block.rs

@@ -7,7 +7,9 @@ use criterion::{criterion_group, criterion_main, BenchmarkId, Criterion};
 
 use zebra_chain::{
     block::{
-        tests::generate::{large_multi_transaction_block, large_single_transaction_block},
+        tests::generate::{
+            large_multi_transaction_block, large_single_transaction_block_many_inputs,
+        },
         Block,
     },
     serialization::{ZcashDeserialize, ZcashSerialize},
@@ -26,8 +28,8 @@ fn block_serialization(c: &mut Criterion) {
             large_multi_transaction_block(),
         ),
         (
-            "large_single_transaction_block",
-            large_single_transaction_block(),
+            "large_single_transaction_block_many_inputs",
+            large_single_transaction_block_many_inputs(),
         ),
     ];