Merge #17192: util: Add CHECK_NONFATAL and use it in src/rpc

faeb666536 util: Add CHECK_NONFATAL and use it in src/rpc (MarcoFalke)

Pull request description:

  Fixes #17181

  Currently, we use `assert` in RPC code to document logic and code assumptions. However, it seems a bit extreme to abort all of Bitcoin Core on an assert failure in one of the RPC threads. I suggest to replace all `assert`s with a macro `CHECK_NONFATAL(condition)` that throws a runtime error when the condition evaluates to `false`. That runtime error will then be returned to the rpc caller and will include instructions to report the error to our issue tracker.

ACKs for top commit:
  practicalswift:
    ACK faeb666536
  laanwj:
    ACK faeb666536
  ryanofsky:
    Code review ACK faeb666536

Tree-SHA512: 9b748715a5e0767ac11f1324a95a3a6ec672a0e0658013492219223bda83ce4b1b447fd8183bbb235f7df5ef7dddda7666ad569544b4d61cc65f232ca7a800ec

test/functional/rpc_misc.py

@@ -23,6 +23,13 @@ class RpcMiscTest(BitcoinTestFramework):
     def run_test(self):
         node = self.nodes[0]
 
+        self.log.info("test CHECK_NONFATAL")
+        assert_raises_rpc_error(
+            -1,
+            "Internal bug detected: 'request.params.size() != 100'",
+            lambda: node.echo(*[0] * 100),
+        )
+
         self.log.info("test getmemoryinfo")
         memory = node.getmemoryinfo()['locked']
         assert_greater_than(memory['used'], 0)