Merge #19698: test: apply strict verification flags for transaction tests and assert backwards compatibility

5786a81 Verify that all validation flags are backward compatible (gzhao408)
b10ce9a [test] check verification flags are minimal/maximal (gzhao408)
a260c22 [test] Check for invalid flag combinations (gzhao408)
a7098a2 [refactor] use CheckTxScripts, TrimFlags, FillFlags (gzhao408)
7a77727 Apply minimal validation flags to tx_invalid tests (gzhao408)
9532591 [test] add BADTX setting for invalid txns that fail CheckTransaction (gzhao408)
4c06ebf [test] fix two witness tests in invalid tests with empty vout (gzhao408)
158a0b2 Apply maximal validation flags to tx_valid tests (gzhao408)
0a76a39 [test] fix CSV test missing OP_ADD (gzhao408)
19db590 [test] remove unnecessary OP_1s from CSV and CLTV tests (gzhao408)

Pull request description:

  This uses the first 4 commits of #15045, rebased and added some comments. The diff is quite large already and I want to make it easy to review, so I'm splitting it into 2 PRs (transaction and script). Script one is WIP, I'll link it when I open it.

  Interpretation of scripts is dependent on the script verification flags passed in.
  In tests, we should always apply **maximal** verification flags when checking that a transaction is **valid**; any additional flags should invalidate the transaction. A transaction should not be valid because we forgot to include a flag, and we should apply all flags by default.
  We should apply **minimal** verification flags when asserting that a transaction is **invalid**; if verification flags are applied, removing any one of them should mean the transaction is valid.
  New verify flags must be backwards compatible; tests should check backwards compatibility and apply the new flags by default. All `tx_invalid` tests should continue to be invalid with the exact same verify flags. All `tx_valid` tests that don't pass with new flags should _explicitly_ indicate that the flags need to be excluded, and fail otherwise.

  1. Flip the meaning of `verifyFlags` in tx_valid.json to mean _excluded_ verification flags instead of included flags. Edit the test data accordingly.
  2. Trim unneeded flags from tx_invalid.json.
  3. Add check to verify that tx_valid tests have maximal flags and tx_invalid tests have minimal flags.
  4. Add checks to verify that flags are soft forks (#10699) i.e. adding any flag should only decrease the number of acceptable scripts. Test by adding/removing random flags.

ACKs for top commit:
  achow101:
    ACK 5786a81
  laanwj:
    ACK 5786a81

Tree-SHA512: 19195d8cf3299e62f47dd3443ae4a95430c5c9d497993a18ab80de9e24b1869787af972774993bf05717784879bc4592fdabaae0fddebd437963d8f3c96d9a73

Author: laanwj