Merge #10275: [rpc] Allow fetching tx directly from specified block in getrawtransaction

Merge #10275: [rpc] Allow fetching tx directly from specified block in getrawtransaction

434526a [test] Add tests for getrawtransaction with block hash. (Karl-Johan Alm)
b167951 [rpc] Allow getrawtransaction to take optional blockhash to fetch transaction from a block directly. (Karl-Johan Alm)
a5f5a2c [rpc] Fix fVerbose parsing (remove excess if cases). (Karl-Johan Alm)

Pull request description:

  [Reviewer hint: use [?w=1](https://github.com/bitcoin/bitcoin/pull/10275/files?w=1) to avoid seeing a bunch of indentation changes.]

  Presuming a user knows the block hash of the block containing a given transaction, this PR allows them to fetch the raw transaction, even without `-txindex`. It also enables support for getting transactions that are in orphaned blocks.

  Note that supplying a block hash will override mempool and txindex support in `GetTransaction`. The rationale behind this is that a transaction may be in multiple places (orphaned blocks) and if the user supplies an explicit block hash it should be adhered to.

  ```Bash
  $ # a41.. is a tx inside an orphan block ..3c6f.. -- first try getting it normally
  $ ./bitcoin-cli getrawtransaction a41e66ee1341aa9fb9475b98cfdc1fe1261faa56c0a49254f33065ec90f7cd79 1
  error code: -5
  error message:
  No such mempool transaction. Use -txindex to enable blockchain transaction queries. Use gettransaction for wallet transactions.
  $ # now try with block hash
  $ ./bitcoin-cli getrawtransaction a41e66ee1341aa9fb9475b98cfdc1fe1261faa56c0a49254f33065ec90f7cd79 1 0000000000000000003c6fe479122bfa4a9187493937af1734e1e5cd9f198ec7
  {
    "hex": "01000000014e7e81144e42f6d65550e59b715d470c9301fd7ac189[...]90488ac00000000",
    "inMainChain": false,
    "txid": "a41e66ee1341aa9fb9475b98cfdc1fe1261faa56c0a49254f33065ec90f7cd79",
    "hash": "a41e66ee1341aa9fb9475b98cfdc1fe1261faa56c0a49254f33065ec90f7cd79",
    "size": 225,
  [...]
  }
  $ # another tx 6c66... in block 462000
  $ ./bitcoin-cli getrawtransaction 6c66b98191e9d6cc671f6817142152ebf6c5cab2ef008397b5a71ac13255a735 1 00000000000000000217f2c12922e321f6d4aa933ce88005a9a493c503054a40
  {
    "hex": "0200000004d157[...]88acaf0c0700",
    "inMainChain": true,
    "txid": "6c66b98191e9d6cc671f6817142152ebf6c5cab2ef008397b5a71ac13255a735",
    "hash": "6c66b98191e9d6cc671f6817142152ebf6c5cab2ef008397b5a71ac13255a735",
    "size": 666,
  [...]
  }
  $
  ```

Tree-SHA512: 279be3818141edd3cc194a9ee65929331920afb30297ab2d6da07293a2d7311afee5c8b00c6457477d9f1f86e86786a9b56878ea3ee19fa2629b829d042d0cda