Merge bitcoin/bitcoin#31784: test: added additional coverage to waitforblock and waitforblockheight rpc's

7e0db87 test: added additional coverage to waitforblock and waitforblockheight rpc's (kevkevinpal)

Pull request description:

  Similar to bitcoin/bitcoin#31746

  This adds test coverage to the `waitforblock` and `waitforblockheight` rpc's by adding a test to assert we get an rpc error if we include a negative timeout

ACKs for top commit:
  Sjors:
    utACK 7e0db87
  Prabhat1308:
    ACK [7e0db87](bitcoin/bitcoin@7e0db87)
  brunoerg:
    code review ACK 7e0db87
  BrandonOdiwuor:
    Code Review ACK 7e0db87

Tree-SHA512: c3b1b3a525e91e0092b783d73d2401126e3b8792a394be00374258f20cf3d619498e6625d3aad5e5ced29509c5eac828ee03c4ee66ba405b91e89be7e8b07311

Author: fanquake

test/functional/rpc_blockchain.py

@@ -535,6 +535,7 @@ def _test_waitforblock(self):
 
         self.log.debug("waitforblock should return the same block after its timeout")
         assert_equal(node.waitforblock(blockhash=current_hash, timeout=1)['hash'], rollback_header['previousblockhash'])
+        assert_raises_rpc_error(-1, "Negative timeout", node.waitforblock, current_hash, -1)
 
         node.reconsiderblock(rollback_hash)
         # The chain has probably already been restored by the time reconsiderblock returns,
@@ -589,6 +590,7 @@ def assert_waitforheight(height, timeout=2):
         assert_waitforheight(current_height - 1)
         assert_waitforheight(current_height)
         assert_waitforheight(current_height + 1)
+        assert_raises_rpc_error(-1, "Negative timeout", node.waitforblockheight, current_height, -1)
 
     def _test_getblock(self):
         node = self.nodes[0]